IE ads have been all over the map for me. Haven't seen centering but I've seen ads where the text rotates like an animated gif for a few days and then that's gone. URLs are gone one day and back the next. If ads go back to centered, I'll be furious. Can't build a house on quicksand and textual ads seem a lot like quicksand these days. One experiment improves CTR, the next destroys it. Is this ever going to end? Never mind, it's a rhetorical question. Of course it won't.
Round arrows, rectangle arrows, rounded rectangles oh my. What's next, triangles or maybe octagons. Hey, maybe a pentagram would work.
You may not but a large portion of the world does. I avoid it like the plague too but it doesn't change the fact that people use it and you can't predict what's going on in that environment from day to day where Adsense is concerned.
That sort of sums up Adsense from the day it was born but seems more on point the last year or so than ever. A perpetual state of flux seems to be the norm these days and I think it accounts for people's strange off and on days more than most realize.