The +2 skill / +2 skill feats and Skill Focus for +3 to one skill are, in my opinion, some of the worst feats printed. They pad out the two page feat list in the PHB well enough, but they don’t really do anything of note.
Skill Focus remains unchanged. It gives a +3 bonus to one skill and serves as a semi-useful prerequisite feat tax for entry into various prestige classes or other options.
The remaining skill feats now serve an additional purpose: Granting additional class skills. Each feat still grants +2/+2 but also grants a new class skill. Each can be taken twice to gain the second skill as a class skill.
Take, for example, the Acrobatic feat. This feat gives a +2 bonus to both Jump and Tumble checks. It also gives you the choice of adding either Jump or Tumble to your list of class skills for all of your classes. Say you choose Tumble as a class skill the first time. The second time you choose the feat, you gain Jump as a class skill; however, you don’t increase the bonus on skill checks. That remains at only a +2.
I have added several additional skill feats which have different skill selections associated with them. I’ve also added one for each saving throw, giving a +1 bonus to the save and a +2 to a skill, just to add some variety. These additions are primarily because I like to give these feats out for free in games I run as a perk for writing a good backstory or taking time in game to train or otherwise expand a character’s non-combat abilities.
Skill feats still don’t do anything very interesting by themselves; however, I do think this change makes them a bit better than they originally were. A skill feat effectively lets you meet cross-class skill prerequisites by paying a feat tax, allowing players to build a wider range of interesting characters.