SF4 tech has evolved since it's release in 2008, at the current stage it is really fucking deep. Seeing how they wanted to remove a lot of the tech from that game and make it more "fair" there's a huge doubt in the community that SF5 can reach the same level. They've wanted to remove OS, which is pretty much impossible, but some early beta OS doesn't work anymore IIRC, crouchtech, invulnerable backdashes etc. For this version of SF they wanted to focus on "footsies" and mindgames. All though this being the SF with the most frametraps it's pretty funny regarding the fact that this game goes for the more casual route.