Also, I believe he mentioned Fiora's death which is kinda hard to have happen outside of Colony 9.
You might be right.
The only character I found 'less useful' was Sharla, btw. She'd basically come along if I wanted "less of a pain in the ass", but Riki and Shulk tended to do alright for healing and were better at killing things.
Sharla would be better if she didn't always kill your Combos with her almost solid Blue Arts pallet and can't use her Talent Art since it causes her to shut down for the rest of the Combo (and IIRC, while it doesn't completely shut down the Combo when her turn rolls around again, I think she ceases to contribute to the preservation of said Combo which might as well cause it to shut down anyways).
That said, I think the funniest thing I ended up doing with Sharla at the endgame was stacking pretty much every Damage Reduction skill in the game (since she gets like the biggest and most expensive one for free) along with top tier HP, Muscle & Ether Def Up gems to turn her into an even better tank than Reyn (bonus points for her healing arts drawing more aggro more reliably and consistently than Reyn's Talent Art).
Unfortunately, shenanigans aside. Sharla's at her highest relevance during the Bionis' Leg/Colony 6 segment since she's not so reliant on Shulk's Monado Enchant Art and you don't have somebody more interesting to replace her with yet. Beyond that, all she has is her healing which makes fights take longer (thus necessitating the extra healing she brings) and her anti-air qualities which aren't that impressive in Satoral Marsh (due to most airborne enemies in that region being huge fuck off level 75-80+ enemies). It doesn't help that she's pretty useless against Ether based enemies as well (not that that ever really comes up). But by the time you're rolling in Mechon again, you'll be up in Eryth Sea with A Certain Magical Railgun on your team who does everything that Sharla does but better (save for healing which is kind of a waste for her). I guess you can at least use her during the segments where Shulk is literally at his worst (and this particular limitation is why I'm baffled by Smash Bros. For's use of the Monado mk1 for Shulk, given many of his opponents and the constraint it should still be operating on).