Most other games only have limited gameplay so you can't really compare them on anything, only on opinions.
Because, while GW2 has different playstyles in the MMORPG genre, Far Cry 3 has different playstyles in the FPS genre, and ME3 has different playstyles in the 3rd person RPG genre, etc.
GW2, while offering many playstyles, tends to favor some playstyles over others. This can be said for any other MMO, including WoW. that's the whole point of MMO's -- actually, RPG's in general -- because their whole purpose is to appeal to the broadest audience possible.
You can't just pigeonhole games based on your playstyle. I don't find XCOM to be very appealing to my kind of gaming, but I'm not gonna sit here and say it's objectively not as good as the ones I enjoy, because that would be completely incorrect.
Regardless, I haven't even seen GW2 win any GOTY awards yet. XCOM seems to be dominating the media awards, with Far Cry 3 and Mass Effect 3 pulling wins in a couple magazines.