Don't assume you talk for the MMO community because you are a member to a few forums where you all cackle like women at lunchbreak.
AoC did not die because of sharding ... it was never the issue or cause - AoC died to the fact it was a poor game, rushed out with so many issues it was just laughable how anyone could even release such garbage. It was dead upon release. Embarrassing really.
Sharding (instancing) is a brilliant concept - it reduces stress on hardware, software, server, client - which for me as a player is brilliant. The worst thing for me playing a video game on-line - is stuttering, lagging - something slowing the performance of my network, my game etc down - hindering my experience of enjoyment.
I know you are all still there - I seriously really don't need to see a million people questing - I really don't. When I do need you for heroics, operations, flashpoints people are still there. And if I really have to see you - I can either A) TP to the instance you guys are in or B) Just type in general chat to talk to you - I really really don't see the problem - but maybe I am just a old un-sociable git who doesn't understand the MMO part ... /shrugs
Now, I am going to go there - GW2 will fail horribly because they don't realise what their "innovate" ideas is going todo to the masses, sitting at home with their copper-wired "superfast" broadband and "pro gaming rigs" from best buy ... and it's the casual masses paying for the games - not some minority rp *** or emo MEMEMEME generation or a die hard [enter any game] fan.
And it will be a shame because GW2 looks really interesting.