outside of looking better how is it -definitively- better?
half the game is designed around a fukking comeback mechanic 
i mean its dope but no buildings have been crushed
It got rid of most of the zany and cheap bullshyt. Things like invincible back-dashes and trades into full meter combos are gone (also juggle comboable supers always get the full super, rather than all the wonkiness of IV's Ultras of who gets a full super vs. who's get half or even full whiffs, even if it should theoretically combo). shyt, pretty much all supers follow the games intended mechanics of how they're suppose to work in combos all across the board . Also, there's a lot less overly long-just-for-the-sake-of-being-long combos (that shyt is for mahvel vs. and anime fighters, not SF), only supers can chip kill (which greatly reduce guaranteed, uncounterable win situations), reduced throw range, better balance of normals priority (with decrease in high damaging, overly reliable jab combos), vortexes aren't as overly reliable, practically eliminated excessive runaway tactics, & high emphasis on full commitment moves defeats a lot of YOLO and flowchart shenanigans.
Also, peep game at how much the animation are much smoother now.
No, that's Street Fighter IV.
Also, a lot of folks want to compare the last version of SFIV to this one, which isn't fair, considering it went thru like 5 or 6 updates to become the game that that is. It's more fair to compare vanilla IV to V at this point, which did not have double the cast and supers and whatnot, to which a lot of folks like to bring up in their debates between the two games.
Lastly, the main reason why "buildings weren't crushed" is due to all the negative backlash Capcom got for shytting the bed on so many other factors about the game that is outside of the main gameplay.