I got the full version (because of price drop) and really don't understand why people claim the game's so bad. Why? Sure, there are some annoying bugs and the environments lack variety but IMO it does compare favorably with Diablo 2. Talking about WoW killers is silly, it's an action hack & slay and appeals to a completely different demographic than WoW.
I like the weapon upgrades and customization, you can do some sick stuff with that and get weapons that excell at what you need (e.g. I have a weapon with 100% shield penetration, another one with all kinds of area damage, ...). Upgrading also means you don't have to abandon your old weapons soon, my main weapon at level 19 is one I found at level 3 or so and it still works great because of all the upgrades.