WoW characters can survive walking space, have their soul taken, be stomped by people whos toe is larger than them, can walk through time freeze effects, swim in lava and have all their skin and organs ripped away from them and keep on fighting, healthy as a doorbell
Gouki can fight his brother in magma completely unharmed, his brother who hits as hard as he does (Island destroying)...Really I do not have to bring up anything else, no WoW character can take being hit with enough force to destroy/sink an island.
Since the hole in fact is sustaining itself, it's large enough. Can't say how large it actually is, since WoW doesn't scale properly.
Are we talking about the heroes here, or any character? There are an high amount of characters that can survive an attack that would destroy an island.
My point with listing that was not to compare the heroes to Akuma, but to point out the fact that it's not as simple as to say "if WoW characters can survive it, so can he". Warcraft heroes resist things that would stop even Superman. Not saying anything in Warcraft could ever defeat Superman, or even come close (Although I would have a good bet on the Pantheon and I'm not counting Nozdormu).
1. Not necessarily, no. While in WoW I have no doubt it does, but IRL? A hole of that size may not, which means we cannot say its power, at least to my knowledge.
2. I am talking about your garden-variety WoW hero.
I bet they can, magic and all.
Edit: Seriously, I have been looking through Warcraft lore for eons, what has this guy actually DONE?
Traveled cosmical distances in very little time, mentally scanned the entire planet, shown potent cosmical powers and has had one awesome dialogue after the other.
In short: Nothing outside gameplay and briefing of lore.
If awesome Dialogue grants victories then Wesker is god tier. The similarity in names does seem to be the main factor and if I'm right isn't Algalon Mr. constellation looking guy that took like 20 characters to beat in like 8 minutes and that was a fast battle? Some video Q showed me a while ago.
Algalon would not survive against Akuma in actual combat, should he be hit, as there's nothing implying he would, but he could teleport him into outer space and win through that. It is not a direct kill, but victory non-the-less.