Well..I like X8 mostly due to it's soundtrack and Zero's weapons >3>
That's where my enjoyment comes from.And some of the boss battles. For me it's gennerally hard to enjoy something. The games I enjoyed the most get replayed by me the most....I've played each of the X games once (besides X1 which I can replay any day without getting tired of it)
There was literaly nothing for me to return to after playing the rest once...
Unfortunately music is another area where it falls short for me. Its nice, but only a few tunes stood out to me. Jakob, both Sigma battle themes, Lumine's themes, and Vile's theme I guess. The other stage themes are somewhat forgettable. im of the midn that X8 relies way too much on sounding like rock music with guitars and such, and ends up just feeling hollow. Or maybe I just dont like the guitar type they use for everything.
Zero's weapons WERE nice. So were Axl's. I loved the ice gatling. X however, got sort of shafted, as almost all of his weapons are useless unless he's grounded, or just kind of useless/cumbersome in general.
The least they could've done is just given the air dash to regular X and scrapped the Falcon Armor altogether, but they decided to wait until X8 to do that.
X7 started that, as RMZX just stated.
That is however something I am against. Mainly because the usual point of how X works is that he has little mobility, and requires his armors in order to gain extra mobility like the air dash. Having it from the start makes the leg parts obsolete without giving them better more creative functions, which X7 and 8 sort of failed at, since the glide was all sorts of stupid and giving you a shadow dash dont quite cut it.