Replacing nebulously defined background features with feats makes certain amount of sense. The former were rarely used and tended to work rather differently than rest of the game, so were a source of confusion and debate. That being said, I think some flavour is lost is the process, which is regrettable. Also, as the old features were not particularly useful, they were really not part of optimisation, just a nice ribbon, but feats are a bigger deal. This makes choosing background more of a thing that is subject of optimisation rather than theme. And of course baking ASIs into it makes this even more so.
And, yeah, the ASIs. What a mess! I was fine with them being tied to the species, though there could have been more flexibility. (Perhaps one fixed, one floating, but not necessarily to any stat. E.g. halflings might be unable to put their floating to strength.) But ultimately it seems silly to me that gnomes and halflings are just as strong than humans or orcs. I know a lot of people just treat ability scores as numbers that do not really represent anything, but if they're that then I think we might just as well get rid of them. To me the purpose of RPG rules is to represent the fiction, and if they cannot do that they serve no purpose.
But linking things to backgrounds is much worse. Some people felt species ASIs were racist, but that required interpretation, to see the species as allegories to human ethnicities. (which is valid, but it is just one interpretation.) But what we have in 5.5 is direct, no allegory or interpretation needed, classism. Nobles in D&D land now objectively are smarter and more charming than stupid and ugly peasants! And as people optimise their characters, these class stereotypes become part of the games. No magical geniuses from humble backgrounds etc. And of course "the biological essentialism" still exists in the species, and it does as long as they have any mechnical differnces.
Now completely floating ASIs are silly and inelegant. First we buy ability scores, then we choose a few points more using a different method. So if the ASIs not tied to any other choice (which seems to be what most people want) then they should just be removed and the point buy budget and caps to be increased.