why should we see it as an "excellent fighting game", when it's missing some of the most basic aspects of the street fighter series, that SFIV made sure to bright back?
where is the fireball game? In SFIV, fireballs at medium range (where you could anti air on reaction) and short range (as a poke) were a very significant part of the neutral game. Aside from guile, fireballs are almost non existant in SFV.
anti airs have also been a mess. Instead of having to use the intended move for anti aring (medium/heavy normal, or a shoryuken, with it's motion), people could use anti air jabs. Then they nerfed shoryukens, and as a result they weren't good for anti airing anymore. They fixed shoryukyens, but anti air jabs are not really gone yet.
And much more than others have already gone over in the other thread we had some days ago (so there's no point in me going over everything myself).
Just look at ryu. In SFIV, he could play at high level with a combination of mid/close range fireballs + shoryuken anti airs + poking with great mid range normals + reaction whiff punishing with sweep/crouching medium quick. In SFV there's game mechanics/design decisions to get in the way of each of those things.