However, there is mention of including a Perform skill in the GM section...
I missed that. But I think it says something about the designer's view of mission non-critical skills like Perform that it wound up as a mention, not in the actual skill list. BTW, I really like the way the SW books include sidebar stuff like that. WotC products would benefit from (more of?) that kind of thing.
1. there are more skills in SW than in 4e;
Not by much. Several SW skills (Shooting, Throwing, Fighting) aren't handled by the skill system in 4e, and Guts isn't handled at all (to name 4 skills).
Besides SW uses the same
kind of skills as 4e: extremely broad categories which ignore specifics. A SW character with Piloting can pilot any vehicle that exists in the setting. In both systems, Stealth covers a range of sneaky activities -- in fact, SW's Stealth is even broader than 4e's -- it includes everything except picking a lock.
2. the Knowledge skill is closer to 3e's knowledge skill and the GM can make them broad or narrow as they deem, necessary, for their campaign.
This is true... with the caveat that the SW rules clearly state a player should only pay for skills which they have to roll tests for at least twice per session. Which places the focus squarely on skills which are actively used in the game, and not just present for theoretical PC well-roundedness, or as nod towards some form of "simulation".
The implication is skills that are mainly decorative/tangential to actual game play should be free, or absent from the character sheet entirely.
3. The player has control of making his or her character just as skilled as they choose to be in a particular area. Decide how good you want to be and buy your skill to that level. There is no +1/2 level bonus. getting in the way?
Strictly-speaking this is right... but thanks to differences in the task resolutions systems (mainly via the wild/exploding die), SW character start off with fairly broad competencies, and while skills don't scale a la 4e'a +1/2 level bonus, neither do the DC/target numbers for most tests (usually 4, right?).
So both systems end up in the same place: with broadly-competent PC's which
excel in a few, specific areas (and whose non-adventure related skills aren't addressed system).
Also, SW, bless it's designers hearts, seems to have avoided the trap of adding more skills to the game willy-nilly through each new expansion/setting book (though they do add quite a few Feats/Edges). They realized by adding more narrowly-defined skills
without a corresponding amount of additional skill points results in over-specialized characters increasingly defined by the things they
can't do, not the things they can.