You can influence the skill outcome to a certain degree, granted you have to have enough AP to execute special skills if that is your aim. From what I've seen, it's broken into a couple A LOT of executions. Here are a couple
1. Attack - No special, so AP is raised)
2. Specials 1 - Use some specials/weaker specials mixed with attacks)
3. Specials 2 - Use better specials but not the best, even if you have the AP to spare)
3. Specials 3 - Go All out with guns blazing ( I believe the choice/leader says, 'Give it your all!' but don't quote me on that).
4. Evocations (Use magic attacks)
5. Heal - Characters heal by means of Magic or items, but characters go into standby (no action taken that round)
6. Heal & Attack - Heal and attack
7. Yellow Text Prompt - Use a character's special attack. I believe this uses up all the union's AP.
8. Standby - Standby.
These are just a couple of the options you can get out of the myriad of choices when fighting. However, once you throw in Critical Triggers (pressing the button that appears on the screen at just the right time), then forget about: WILD CARDS FOR EVERYONE! Actually...unless you master the critical triggers--which isn't hard when you discover that the button choices aren't as random as you think--you might as well shut the game off and sell/trash it. The Critical Trigger literally is the Wild Card that can turn the tides of a battle when things seem hopeless (and they will feel it when you are ambushed by a 4 monster linked battle like I have...frequently).
I think what might frustrate players even more about battles is that even though you see only three enemies on screen, that does not represent the amount of enemies you will fight in battle. As the hero of the game, Rush, represent a full armada of soldiers/leaders, the same can be said of opponents. That 4-linked ambushed i mentioned above? Yeah? Try 15-20 monsters (5 groups of 3/ 6 groups of 3 + 1 group of 2) in battle, all attacking your two squads in the earlier stage of the game with morale at zero. They all decide to attack and take down a squad's leader? Leads to a botch (the game's way of saying the squad is running around with their heads cut off, AKA can't give them orders).
Never be Reckless.
Never be Greedy.
But you know what? It's that this game isn't going to hold your hand that I love it so much. I actually feel a little hopeless some battles, like I'm feeling what it must feel like for enemies when I come towering into battles and winning, getting my 2 exp, 1 gold and moving on to the next fight. I've Game Over-ed at least 15 times...but I'm still coming back.
Also, leveling is completely random. During a run of the game, a couple of my skills upgraded, but I died and had to restart. Went through the same motions and fought the same enemies using the same tactics, but did not get those upgrades back. There cannot be a logical system in play if my motions were near identical to the last (Alright, I admit I circled a monster like duck-duck-goose before I encountered it). There's definitely a random element to leveling/skills.