100 of hours of gameplay?
Seriously I got bored by the end of the first week (and not playing it for 8 hours a day either) when my Warlock was around level 40ish...
The game is aimed really at children - click a monster press your hot-keys as fast as possible, rest and repeat.
At least in other games you get to vuln, bane, cast protection spells choose what kind of spell you would like (i.e. fire, lightning) and thus represented in the damage you do.
£8.99 is a lot of money for some people as well and they may well enjoy it for a few months until they reach game-over with everyone then going into instances to try and grab a bit of loot that they have a one in x (team party size) chance of getting and then if you dont get you have to repeat it over and over again...
Oh and then theres the cost of the addons...