I haven't booked in the last 24 hours, but as of last week I could still select exit row at booking. Although I took a flight on AS this week and there was a glitch with upgrades. The upgrade just wouldnt clear in advance despite U space available and ultimately was cleared by the GA. I was on a non-saver fare. The website has felt glitchier the last 1-2 weeks and I've seen new interfaces on & off too. Maybe just IT issues.