I think you're being too reductive. The point isn't that you're unable to do it that way, the point is there are far more effective ways to do things. But obviously you wouldn't know that since you've never tried.
I mean I got through the game in 37 hours which seems about right, I got one game over and it wasn't on a boss, my approach seemed effective enough. Maybe it would have been 35 if I'd switched up weapons? It isn't like I crawled over the finish line in 100 hours.
I'm not saying you can't have fun with the battles (when the camera behaves) but in previous games you have a magnetic cave where metallic weapons should be replaced by wooden ones,or a ninja steals all your materia and you're forced to use weapons, bosses who's elemental weaknesses cycle and you have to react to it etc.
That is the sort of thing I would have liked to see. Give me a dungeon where warp striking + swords don't work and I have to figure something else out. It's not on me to try out all the weapons in the game, it's on the developers. The default way of doing things in any game is what the majority of players will do, it's the experience most will have.
Personally if I was tweaking the battle system I would
1) Make various enemies more resistant to things, warp-striking, magic, physical attacks etc.
2) Allow the player to cycle through all the characters, if I want to control Ignis and his different weapons and abilities let me
3) Have an actual cure spell that isn't some side effect of an offensive spell.
4) Following on from that reduce the potency of healing items.
5) More commands like Ignis' regroup Technique.