^ FF games are certainly not the best of the JRPG world. They are most well-known in the West because they were produced by a big company who had the money to work on English localization.
I would not group them with Diablo, or any Western RPG at all, but if you want to compare, I think they are rather more like IWD games, or some western TBS games (see Disciples).
Combat requires little thought beyond knowing what to use at a certain point, something that's applicable to many games that don't fall into the RPG genre, to compound that, there's little character customization in most Final Fantasy games, your statistics are automatically improved, characters typically begin with preset classes and a few minor alterable traits.
This changes vastly from game to game. FFII and FFIX and the post-PSX games were the ones that really restricted player's leveling choice. As a tradeoff, they offered many characters to use, so the player had to find a good party combination for specific fights.
FFI offered you to choose your party at the beginning (much like in D&D games), and then you leveled the party you chose. You could have 4 warriors or 4 mages or any possible combination.
FFIII and FFV both had extensive job systems that allowed you to mold every character (all of them started with no class) into anything you wanted. Stats also depended on what class you leveled up as.
FFVII and FFVIII gave you basically "blank slate" characters which you could level-up in any way you want. The stats and abilities heavily depended on materia/junctions/GF, so you could not say it was "automatic". The player had to choose what to use. In FFVIII each character would get "attuned" to the summons and use the ones they leveled up more effectively.
I'm also a firm believer that a good story cannot exist without good writing, and that was something entirely absent (at least with my standards) in the Final Fantasy series, dialog was very dry, exposition typical and generic.
Early FF games (NES, SNES) did not focus heavily on writing, but instead on gameplay, just like most games of their age. A lot of early FF translations also sucked balls. On the other hand FFVI, FFVIII, FFIX, FFX all have well-written (if "cheesy) stories that keep you interested in the game.
All of that being said, I prefer "tactical" JRPGs that make full use of TB combat, like FFT, FFTA, BMW, Hoshigami, etc etc