I wouldn't be so quick to write it off, the engine may be a bit dated, but at 2560x1080 in DX11 64bit mode with Ultra settings, 16xAF and 8xAA it still looks great especially in the new zones (Personally I considered the grainy style of GW2 to be inferior by comparison). Further expansions/updates will only improve things more and the rate at which new stuff is added will extend the games lifespan further.
If a player (not accusing you of this) will just sit there complaining they like raiding and don't care about Wow'emon, brawlers guild, scenarios, etc then the game will seem dying. However if they enjoy/embrace the new stuff then its going from strength to strength, the is much more to "do" today than the was in vanilla and while the importance of 5 mans has significantly decreased from the BC/LK days other things have been added to take their place like LFR, brawlers, Wow'emon, scenarios, etc.