I know UBIsoft was wary of EA trying to take over, it seems to me like the recent move by EA was a substitute for that. I'd really hate to see ubisoft bought out by EA.
Ubi wont sell EA the shares needed to get controlling majority. It's also not EA as a whole who owns the shares. It's a division of EA located in europe somewhere. Interesting enough, I wonder if EA is considering SCI since it was recently anounced ubi was interested but desided to pass up buying them (refering to ownership of everything eidos).