What does that have to do with Star Wars? Well, it highlights that, by and large, the skill list in Edge of the Empire is a nice middle ground between the two most recent editions of D&D, and is possibly my favorite skill list of the games I've played or read (with the caveat that I still like the freeform Backgrounds of 13th Age better than any skill list).
The strongest element of the EotE skill list is the granularity of its social skills, to the point where it's actually interesting to build and play a "party face." Going back to D&D, you'd usually just bump up Cha as high as it would go, and most of the social skills were conveniently tied to that ability score (with the exception of the Knowledge skills that often help when going into social encounters). In EotE social skills are widely spread amongst the different Characteristics: Intellect for the various Knowledge skills, Presence for Charm, Leadership, Negotiation, and Cool (which opposes certain social skills, and may be called upon as a "defense roll" as opposed to the NPC rolling the skill), Willpower for Coercion and Discipline (which opposes the social skills that Cool doesn't), and Cunning for Deception, Streetwise, and possibly Perception (if you're wrapping Insight/Sense Motive into that skill). Now it's a lot tougher to shortcut that "face" build!
The social split encourages teamwork in social encounters, since no PC is likely to have equally high values in 4 of the 6 characteristics, and that's a lot of individual skills to keep up with. Rather, the system seems to encourage PCs to pick an aspect of social encounters that they can contribute well in, so everyone can feel the need to participate in some way. Of course you can still make a more focused "face" character, but they'll still be better in some areas than others depending on their highest Characteristics (likely Presence), and it will be XP-intensive to keep all of the requisite skills high. More important are the Talents, especially in specializations like Politico, which give the "face" a huge edge while still letting anyone else with a decent dice pool succeed (if, for example, the party is split).
This works because humans are social creatures, and there are a lot of different ways that we interact with each other. Very few people can say they're equally comfortable talking with anyone; a senator, a scientist, a drunk at the bar, and a black market arms dealer are all going to be very different experiences which require very different approaches. By comparison, I'd say that the D&D social skills (or, more accurately, the Charisma attribute) are overly abstracted and thus less capable of modeling these nuances. Of course it helps that EotE is designed as a game where you survive on the fringes of the Galaxy, probably by navigating various social opportunities, whereas D&D can support social adventures but is ultimately built on the premise of killing monsters and taking their stuff.
I think I've made my peace with the Cool/Discipline split. They could certainly be combined into one skill pretty easily, but explanations for the reasoning behind the split on the Order 66 podcast brought me around to the designer's line of thinking as well. Actually, it was encapsulated best by the memorable quote from a listener in the chat: "Han Solo has Cool, stormtroopers have Discipline." In other words, Han Solo projects a certain cocky confidence, and it lets him do some pretty daring stuff like chase a couple of stormtroopers down a hall on the Death Star, but once he sees a room full of reinforcements, he panics, crumbles, and runs the other way. Stormtroopers, on the other hand, probably look pretty awkward in most social situations, and don't project much beyond simple uniformity. But when a firefight breaks out, they've got the military training to not panic, and to just follow their orders. From a general gaming perspective most systems would wrap both into a single concept, but for modeling a particularly iconic scene, I think it works for a Star Wars game.
Cool is ultimately more social; making yourself look like you belong, and also being able to read everyone else in the room well enough to take advantage of opportunities (which is why it's also an initiative skill). Discipline is just having that inner, well, discipline; you stick with what you've got to do despite what's going on around you.
My group (somewhat erroneously) has been oversimplifying this dichotomy into Perception = active, Vigilance = passive. It's easy to fall into that trap, partially because the case for splitting Perception into two different skills is, in my opinion, the weakest of the "split skills."
I get some of the reasons for the split. It provides more freedom with Characteristics for a character that wants to be perceptive, since you can achieve the concept with a high Cunning OR Willpower. There's also a LOT to be said for splitting it up when you're using one of the skills to determine initiative, especially considering that many gamers already consider Perception to be a "super skill" in most games. But there are also a lot of negatives that go along with the split.
For one thing, Perception already covers a lot of what Vigilance is supposed to represent. Perception is stated to be applied when looking out for a potential ambush. And yet, Vigilance is supposed to be a sort of passive perception with regard to sensing imminent danger (which is why it's used for initiative). But that basically relegates Vigilance to initiative rolls proper, and the little side example of ret-conning that a character brought along some small piece of gear (which Destiny Points can already do).
More importantly (since EotE is a narrative game), it can be tough to explain why a PC that's terrible at noticing things in general (low Cunning, no ranks in Perception) is all of the sudden amazing at noticing certain situational things (i.e. danger), especially if Perception is also useable for detecting danger. For example, I've done a lot of invasive plant control (walking around the woods searching for a specific shade of green, shape, etc., often at a distance) and bird surveys (mostly by sound). These activities require a lot of active concentration, and would fall under the umbrella of Perception. But the thing is, I'm generally more alert to what's going on in my environment (I notice a lot of small details while out hiking) precisely BECAUSE I have prior experience focusing on very active perception. The more you do something, the more it becomes second nature, and you can do it without thinking about it. I just can't imagine anyone being particularly vigilant if they didn't have that kind of awareness that would fall under the Perception skill, and that's a pretty big narrative disconnect to me.
Obviously re-combining the skills is not going to be an effective solution at this point. Vigilance is too tied up into the initiative system to get wrapped up into Perception. Perception + initiative would be too much of a no-brainer pick that no PC would be built without it. Plus whichever Characteristic you didn't use would go down in value, as both Cunning and Willpower are already associated with relatively few skills. So I think the biggest tool for dealing with the issue is probably awareness of the issue. If the skills are so tied together anyways, why not ask the player to "roll a Perception or Vigilance check," embracing the fact that they're often interchangeable? Or you can go the opposite route, and in the case of spotting an ambush you can houserule that it's actually more appropriate to use Vigilance than Perception. Maybe it might help to think about Vigilance as the "Resilience" of Perception; it applies when you're exhausted or distracted, and being good at Vigilance but bad at Perception simply means you have a lot of mental endurance (or you just get really paranoid when you're tired). And, of course, there's no harm in favoring Perception over Vigilance since initiative is such a high stakes roll. Viewing it from the initiative lens, you could even think of Vigilance more like having fast reflexes - you didn't notice the attack before anyone else, but you sure can react to it faster.