There are certainly multiple levels here.
First, some of the styles need buffed in general. Protection, Great Weapon Master, maybe two weapon fighting. I actually think with the change to Sharpshooter, Archery isn't overpowered anymore.
Then, frankly, there is no reason to make these feats. I think it is the same type of "simplification" they've been doing in a few places. Since this is a "feature" that multiple classes can get, it is a "feat" instead of something else. But I honestly think making them a list in the Warrior group makes just as much sense.
Especially since the thing I'm already thinking we should do is make a 4th level feat that gives a fighting style and some other general benefit, like the superiority dice and a maneuver. There are absolutely a few classes (currently) who can benefit from fighting styles, and as we expand into having things like Bladesingers and Bladelocks and Valor Bards, it can make sense for them to want the Fighting Styles. I don't think they should be punished for wanting those features by getting something so much weaker than what they could have otherwise gotten. Additionally, for those saying you can take them at 1st level, that is only true if you are part of the warrior group, since they are limited. And, frankly, only Defensive really stacks with the other styles, so there isn't any reason that a warrior is going to want to have it as their first level feat.
Finally, there is no reason to limit these. Rangers can be strength and wield a heavy weapon. Paladins can dual-wield, if barbarians get them in the new OD&D, they can use shields. There isn't any reason to limit these options.