XC 3 COMBAT SYSTEM

As you can see in the other video the combat is fun and interesting, this is where this game really shines. However, the brightness does not last long and after reaching the middle of the game the frustration of not being able to put the classes to the characters you want or how you want, will lead you to assign known classes and with that you finish the game.

For example Noah as FLASH FENCER (Ethel Class) is one of the first classes you get, using a good crits build you can beat the game easily. This is where I feel that this system is inferior to the XC2 system, even completing the filigram scheme of the blades was much more interesting than this.
To stand out in combat you only need three things: i) Know how to position yourself according to your class, ii) Use a combination of pairings, that is, two dps, two tanks and two healers, and iii) Use wisely the chain attacks.

[kalypsothefreak]

I had a slightly different problem. Since playing a class that's reached level cap is less productive than playing a class not already max level, I contestants found myself switching classes to make sure I was constantly ranking up. After I maxed out every class it felt so liberating, and I've been enjoying the combat more ever since

[CritsVG]

For me it was quite the opposite as what you describe in the description, unlocking all classes on everyone motivated me to frequently switch between them ^^ But I can totally see that it could feel like that to some players. Absolutely love the combat though and still want to master the character switching mechanic at some point.

[Zxanonblade]

I don't really understand what you mean by "frustration of not being able to put the classes to the characters you want or how you want" since you can just put the same setup on any character if you have all the different arts, skills, etc that you need.
And for the final note you made in the description, Xenoblade games have never been much about the in-combat strategy anyways. They pretty much always revolve around planning out your build in the menus and then planning how you will use it. Complaining that you only need three things to be good in combat is kinda pointless unless you're adressing the whole series in this regard.
Ultimately, I did beat the game using mostly already known classes, as you said would happen for many people, but that wasn't because of limitations in the combat system, that was due to my own lack of knowledge on if the classes were any good or not.