FFX was simply a much better game overall. Bringing taste isn't really a definite answer on what truly makes a game good or not.
I like FF4 way more than FF7, but there is without a doubt on FF7 being a much better game. Unless you have those that are towards being a contrarian edgelord with popular opinions and tastes.
All the mainline FF games (not counting MMO titles) excel in at least one aspect.
FF1 - Setting the tone for its unique mythos.
FF2 - Password system, character driven storyline, Setting the basis for an entirely new IP called SaGa. Being the most arbitrarily difficult game in its original 8-bit version thanks to auto-targeting not being implemented in the series yet.
FF3 - Creation of the Job System and the first to bring an unappreciated but essential mechanic called Auto-Targeting, effectively washing away the major problem with FF1 and 2.
FF4 - Creation of the ATB system, an even further expanded character driven storyline, fixed jobs to capitalize on character individuality.
FF5 - Job System 2.0, first to introduce superbosses.
FF6 - First to ditch the usual trend of antagonists, first to implement Limit Breaks (though impractical and random), a Magicite System which allowed characters to not only learn spells, but even increase specific stats when equipped, player-made decisions actually effected what character you keep or lose later on in the game.
FF7 - Expands on the Magicite system with Materia that complements special commands and even temporary stat boosts, First to gain mainstream attention as well as use 3D rendered polygons to expand on the cinematic storytelling shown in previous titles. expanded on FF6's Limit Breaks through a meter.
FF8 - Unique Junction System which potentially eliminated the need for mandatory grinding (and potentially break the game), the first to use an original vocal song that won an official music award. One of the most speedrun-friendly games around.
FF9 - First FF game using 3D rendered polygons to go back to the series' NES and SNES roots, first to use the currently unique Active Time Event, an optional feature that allows the player to choose whether to see events happening elsewhere or to skip entirely, making it convenient for speedrunning.
FF10 - Possibly the most accessible in the series, giving a comprehensive tutorial on how spells and unique skills work, as well as a more beginner-friendly CTB system which allows you to not only anticipate the opponents' turn easily, but also control the pace of the battle freely without feeling pressured. Leveling system is replaced with something more visually interactive called the Sphere Grid, which levels specific stats instead of focusing on character levels.
FF12 - Eliminating random encounters by taking a more MMO-style approach, and introducing a Gambit system which automatically configures the actions of CPU-controlled players (and even your own) by order of set priorities. Similar to Grandia, except not really.
FF13 - Expands on the Auto-Battle system in traditional battle settings with a more streamlined, all-purpose Paradigm system. Enemies are given a stun meter to help control the pace of a battle while also providing a challenge by limiting stat growths per chapter.
FF15 - Can't comment on this just yet.