Scales are easy, but getting a good sound is not, especially the subtone (that kind of breathy sound-- think Stan Getz). Building up the diaphragm to move enough air through the horn can be hard for some, especially on the tenor and the larger saxes, (and also against harder reeds). Actually, soprano requires quite a bit of air too. Anyway, alto tends to be the "default" beginner sax because it is easier to achieve a nice tone and the size is manageable for just about everybody. A good embouchure can also be hard to develop. There is the very basic embouchure, where the lower lip curls over the bottom teeth and rests against the reed, but jazz players experiment with these as well. For example, one might curl the lower lip over the teeth and then roll the inside of the lip out to rest against the reed for a brighter, more open tone. This embouchure requires a lot more control from the cheek muscles though.
You're absolutely right, and im certainly no saxophone expert =). But judging from my experience i'd say as an instrument it has a more forgiving learning curve than other winds/brass. A lot of the challenges the saxophone has and the things you pointed out are things you don't really need to worry too much about until you're making the transition from "i'm learning the saxophone" to "i play the saxophone". Getting a good sound and good embrouchure (couldn't remember the word earlier, thanks) is an ongoing process. But to just, for example, play along with a 12 bar blues, thats something i think you could learn in no time.