I feel that General Leo's shtick is that he's the guy in charge of military (ala a Light Brigade commander or somesuch), while Cid and other "Scientists" are running supra sekret science projects in the pursuit of forging some kind of doomsday weapon that'll end up going wild and killing everybody or something (ala artillery cannons), and now the old fashioned commander is looking at said guns and going "What the hell are these even good for? You can't strap them onto a horse!" and proceeds to let the other side walk right off with them, who then proceed to turn them on said brigade and turns the whole lot of them into mulch.
Leo in particular, was too busy going "Just give me a sword and an army of men and I'll take whatever village/town/castle you want. I don't need any of that hocus pocus that those weird witches are flinging around." to really notice or care about Celes, Terra or Kefka (at least until Kefka's destructive tendencies start getting out of hand, while Terra breaks loose and Celes gets locked up while she flounders about with allegiances, but by then its too late). Cid meanwhile literally doesn't know or care about the implications of what he's doing until your party points out that his way was completely pointless and stupid, and even then only Kefka really takes notes. Even with Celes he's basically more of the opinion that doing science to her in order to make her a living weapon was more of a good thing than bad or evil, plus he finally got it right with her. He really doesn't turn it around until after he has to care for her for a full year and is basically on his potential death bed. He's basically just shy of FFVIII's Robin Williams Cid in terms of sheer incompetence.
Also, going back to the Celestina thing, here again is more evidence that the whole Thamasa arc was meant to be much earlier before getting retooled for where it is. Its back to Terra and Locke (a party that hasn't been a thing since Figaro Castle), Shadow, Leo and Celes are on board the Love Boat where Locke and Celes are trying to hash out their relationship over the revelation that Celes is still apparently a member of the Empire, while Terra and Leo are trying to hash out what Terra should do with her 'emotions' and her recent break with the Empire. While sometimes you can run across storylines that have parallel themes, characters or even scenarios; here, it feels far more like the writers came up with two different scenarios in mind, and rather than having to make the hard call and pick only one, they made two characters instead. And then Leo's death scene feels like something that might have had more weight earlier on when Terra was still fledgling through her memory loss instead of well after accepting her Esper side and it would've made more sense rather than Leo getting jobbed by Kefka, who follows up by immediately jobbing Gestahl and your party before Celes turns yet again and Shadow pops in to hold him off somehow.
As for Leo's strategy versus Doma, that's Sieging 101. He did his best Gandalf and told Doma "YOU SHALL NOT PASS!!!" and formed a line around Doma with the intent of cutting them off from the rest of the world, while occasionally sending out a bunch of mooks to try to pry open the doors in the hopes that everybody inside are too tired/hungry/depleted of morale to put up a serious fight (and then Cyan promptly waltzes out and walks all over them). His means aren't all that humane, but that's war. His goal though was to subjugate the people and lands of Doma and put down any organized resistance. Kefka's goal was to end the conflict to his schedule yesterday and cause as much damage as he could while doing it, and he accomplished this by fowling up Doma's entire water table and causing the entire region to be rendered uninhabitable along with killing anyone who wasn't lucky enough to spot what had just happened, regardless of their allegiance. Any value that Doma's property might have had to the Empire, or anybody for that matter, went right down the drain.
As for the Serpent's Trench.
Its not that bad after Sabin's initial trek since every point of interest on his route short of Baron Falls, Gau's hiding place, the Old Guy's house and Nike are all gone/non essential. The big reason to run it prior to getting Mog is to get Gau some of the Rages from the enemies encountered in the Trench since the Aspik Rage has a Bolt 2 equivalent spell (or just Bolt 2) that paired with the General Rage gives Gau some serious elemental coverage for pretty much the remainder of WoB (makes him a solid choice for Zozo, Magitek Factory and Sealed Cave).
You do realize that the landslide that prevented Sabin from just waltzing on over to Le Femme Nikita is gone by the time you actually end up in Nekoah? You can just straight up walk from Nemah to Baron Falls without ever touching the Returners' Base or Lethe River (and the scene that pops up when taking the South Figaro boat to Nihm and back is pretty amusing as well).
And yeah, the big reason to bother running that route at all is to get Mog Water Rondo as its the only time he has an opportunity to battle underwater in the SuperNES and PSX versions. In the GBA and Mobile versions, there's a fight with Leviathan in WoR that can serve as an auxiliary opportunity to learn all of Mog's Dances without having to recruit him in WoB (regardless as to whether you rescue Mog from Lone Wolf or choose the Gold Hairipin, you'll still be able to recruit him in the WoR).
@ aeolus -- On the Shadow note. I'm not going to argue his efficacy in battle because, while I could make a case for the Ninja, he pales in comparison to other cast members. For the hell of it, I will throw it out that should you invest time in his magic the skeans are a suitable and cheap stand in for magic making throw somewhat useful until level 3 spells. Spend your time having him learn buffs and healing and you have unique and versatile character. Genji+death dagger+evade for quick level grinding in certain areas also worked well for me.
Nope. He is a weak link who just happens to be hella- useful in brief specialized circumstances.
The Shadow appeal is his implementation in the script. Think back on RPG's of the early 90's. How many had a character that were optional/quasi-hidden with narrative impact? Not too many I can think of that made it stateside. Furthermore, your decisions directly impact his survival with plot-relevance. These are the points that make Shadow memorable. In short, Shadow is a mechanic within the game for making the player feel as though their decisions have meaning and weight. This is of course common, if not pre-requisite stuff, for more modern RPG's but that type of material was rare in the days of FF6.
But I obviously have a bias here based on fandom and namesake so maybe I'm just over-stating an opinion?
@Glassjawsh -- Since we are talking Shadow I wanna state that the "Shadow save" at the Thamasa incident is a particular favorite instance of mine as well. It makes it all the more interesting when you begin to unravel his identity. Once you "figure it out" and think on his connection to Relm and what is going on its such an "Ah- ha!" moment.
I'm happy you expressed distaste for Leo's status screen pic too. I am firmly in disagreement with whomever thought that avatar for him was suitable.
The problem with Shadow's Genji Glove+Death Dagger+Evade build is when its Genji Glove+Assassin+No Evade due to the Evade glitch. Shadow is naturally better in the GBA/Mobile versions as he has access to Den of Dragons and the items therein, including a brand new ultimate weapon for him (and one that isn't aggressively mediocre), but then so is almost everybody else since that dungeon has items for everybody. That said, he could dual wield Man Eater + Thief Knife for a 20% M.Evade boost, but Thief Knife is kinda weak by the point you obtain Man Eater, and Man Eater isn't all that great either. Also, Genji Shield alone provides a 20% M.Evade boost, let alone the additional 20% Evade in the GBA/Mobile versions.
And Skeans are actually not that efficient past Zozo. Namely because you get Shiva during Magitek Factory who teaches Osmose at a fairly decent rate (and Zoneseek is even more efficient) and that's all you really need to perpetually cast Magic (and an enemy you know you can reliably drain MP from).
That said, I've nothing against Shadow personally. This is just me giving you a hard time since I've only ever really considered Shadow to be okay but a bit too try-hard. His Floating Continent shenanigans are the highlight of his career while the secret sleep scenes and Sabin's scenario are other high points, but he's not nearly the big deal people tend to make him out to be in the long run since he's practically an optional character through and through (ala BoF's Deis, DQVI's Terry/Lizzy, FFVII's Yuffie and Vincent and Xenogear's Esmeralda, among others).