For the last year, I've alternated between WN and American. There's definitely a lot of difference. I, too, usually use my American miles for international RTs, which isn't an option on WN. And up until recently, I was starting to get annoyed with WN, but in the last two weeks, I've had three AA tickets that needed changing, and after dealing with the hassle, I think I'm going to go back to WN, except when I fly into WN-free airports.

The simple fact is that WN makes changing your plans very easy. On AA I buy unrestricted, but discounted, tickets, so although I don't have to pay change fees, I do have to pay the fare difference if I change flights. If I make my change on the day of travel, sometimes that fare difference is significant, because all the lower fares are gone. With WN, I always buy the full-fare ticket (which is usually about the same price as an unrestricted, but discount ticket on AA), so I'm never caught by surprise with a hefty fare increase if I change.

RR tickets are the same way. Even though domestic RTs are usually fairly inexpensive if you plan in advance, WN's RR tickets are better than an advance-purchase American ticket. They're a breeze to book and change, because there are no change fees, and no capacity controls, so if there's an open seat on the flight you want to change to, it's yours. I've gotten spoiled on WN, and I know the next time I redeem an AAdvantage award I'm going to be disappointed at the lack of flexibility.

To address your #s 2, 3 and 4, I usually don't sit in the bulkhead, but I remember those seats having tray tables in the armrest. It's been a while, so I could be incorrect. Did you look there?

Honestly, I usually don't encounter WN FAs that are extra-super friendly, but I've never felt like they were LESS friendly than AA FAs. Every now and then I see an FA on WN that goes above and beyond, and I almost never see that on AA.

If you're not travelling by yourself, yes, boarding is a little trickier. Although it's much more likely that other pax will switch with you, since their seat wasn't really "assigned". You have the same problem if you book late on AA, anyway, and then you have to get people to switch from a seat, which in many cases, they specifically chose.