You could argue, though, that night elves have always had the ability to study arcane magic (obviously, or they wouldn't have done it in the first place) from then to this day, even though the Highborne were banished, there still remained a very high chance of some of the ones that stayed behind to eventually be tempted to study the arts of the arcane.

Conversely the blood elves have had absolutely no exposure to the druidic arts since their banishment.

Also, lol, they certainly don't all num-lock run on my RP realm (Earthen Ring) but when in the roleplaying mood, most do that just for the sake of realism.

If the Blood Elves had gotten druids when the Night Elves had gotten mages, there would have been a riot. The horde would then have more druid races than the Alliance, and there is no way that would have gone over well.

I play on an RP realm, and I do (well, I run everywhere anyway, even if numlock never enters into it). I've seen people strolling along and talking, but they're a bit of a minority.