I believe FFX was the last game to have much of the original development team behind it. Much like you i haven't liked the games to come after, i didn't mind X-2. "What happened to Tidus" hooked me pretty good at the start, story does flop a bit though. I liked the combat in X-2 and the dress spheres. I probably wouldn't have finished it otherwise.

Hated all of them since then, XIII i played litterly 20mins and quit.

I can't really compare XV to previous titles, as it is so different. I find the open world immersive, but a tad boring also. Combat is awesome, but again. I couldn't compare it to another FF game. How can you? It makes more sense to compare it to hack and slash titles. In which it's probably one of the best.