AFAIK I have no experience with that particular rim, but from what I see on various websites there should be nothing wrong with them. I do have Araya rims on one bike and I like them. The cyclone hub should be winner too. That doesn't sound like "entry level" at all. My real point is this - you could swap rims and hubs all day and you'll never notice the difference, all other things being equal. Moving from 36 spokes to 32 or 28 might be noticeable, but there are plenty of great wheels with 36, plenty of TdF wins on them, and zillions of miles ridden in haste with them! Consider Panaracer Pasela tires, maybe 25mm. The most supple and lightest will be folding, and non-Tourguard, though folding (non-steel-wire bead) makes them more expensive. What pressure are you running your tires? "cheapo performance brand" could mean anything, AFAIK, but perhaps that is a specific model we all should avoid, I dunno'.

More to the point, something about the bike isn't speaking to you emotionally. You must have an idealized view that this bike doesn't hit. Before you spend much money trying to "fix" what may not be fixable, try to understand what you really want it to be, what you really want to be different. Perhaps it is overall weight, or shifting ease, or frame dynamics, or how it fits you, or maybe just its appearance or the name Schwinn, or some combination of all those things.. If possible, put in some miles on a borrowed bike to get a sense of perspective. The difference between a good and a great bike can be pretty subtle, and many a mid-level bike is really quite nice. Two bikes which weigh, say, 24lbs and 26lbs will ride about the same, all other things being equal. Changing crank or brakes or gearing won't make much difference. You aren't going to light your own fires with upgrades like that.