Do we want another 10 years of FF14 on this engine?

[Jeeqbit]

Why does everyone have this assumption that the engine is the problem?

It's not. It's related to decisions surrounding infrastructure (dedicated servers vs cloud servers), separation of server machines (such as how you transfer from one server to another for dungeons and the inventory has to be "transferred" with you). These are decisions they made regardless of the engine used and they have pros and cons.

A lot of people attack the graphics, but these are intentional as well and not related to the engine at all. They made higher poly models in 1.0, but they didn't look good next to the lower poly models so they decided to make them all balanced somewhere in the middle with a poly limit they all decided on. The resolution of textures is something that increases with time and the game is 10 years old. A new engine would not mean higher resolution textures. The detail on models and textures is unrelated to the engine because they showed us some very realistic pictures that the engine is capable of and how they are going to increase the light and object limits they had imposed on themselves to support older player machines. The shaders scripts don't ask as much of the graphics card to support older player machines, but they could if SE decided not to care about old machines.

Don't forget that the engine adapted for this game was also used for FF15.

Do we really want another 10 years in this? Or would we rather get FFXIV-2?

The engine can be changed without making an entirely new game. They did it in the transition from 1.0 where a lot of things were preserved including characters.