the term hardcore is loosely used and has no meaning. there was nothing hardcore about FFXI. if you want to see what hardcore looks like you should play eve online or darkfall (two mmo's that i play) and experience having your corps looted upon death.
your basing that the game failed due to techincalities is incorrect. it is a slow paced game. packet latency due to overcrowding would not completely hinder your gameplay. in FFXI when there was 4300+ players on the server there was network lag during battles. i remember it specifically at the dunes camp and pull zones back in 2005. it did not cause people to quit playing.
you do not need more than 30 frames per second to have a smooth experience, either. the game quite extremely well on default settings (ps3 settings) at 720p on an 8800 GTX with quad core cpu. if you wanted to max the game out on that hardware it just would not work, not the game's fault.
like i said, it has failed because players were expecting an improved final fantasy, ffxi-2. one simple improvement? easy....the looking for group mentality took it's toll and players did not enjoy waiting 2 hours for camp and pull leveling zones due to their particular class / job. introduce a server-wide LFG feature that teleports you in the same camp and pull zone that other players have their flags up to battle and level up. you are in dunes with your flag up, a cross-server search gets performed and gives you the option to group up. once the party is full you are all teleported to be with eachother. the server location you are all placed in is random. exiting the zone teleports you back to your original server. server-wide LFG option can only be peformed if you are in the particular camp and pull zone. it's basically a copy of WoW's server-wide LFG.
the burden is on you guys to prove me wrong because i base my arguments on FACTS. there is 5% of the player base remaning. this remaining player base consists of the players that like the game as it was originally designed. what in the world makes these players think they have a right to complaing and whine about keeping the game as is? the game was designed for you 5% remaining FFS, and there is not enough of you to keep it alive, lol! more importantly, how stupid must the devs be to actually not reverse course and go back to the fundementals of ffxi?
you don't take FFXI and strip it's core elements to chase after the "casual" WoW market. hindsight is 20/20. if this came out as ffxi-2 it would not have bombed.