People need to stop thinking how much time you play = how hardcore/casual you are. Hell i had a lot less playtime than many folks in xi and accomplished more and played less but i still considered my self hardcore. A hardcore gamer is someone who plays anything and learns the ins and outs of a game not time spent. I always hear retarded ppl say i play FPS cause it has blood that makes it hardcore or some other stupid reason.

If you wanna know hardcore was the RDM taru in XI who learned everything about his class and proceeded to solo many high lvl monster that others could not do that's hardcore someone who took time to learn everything about the game.

Now back to the topic, while i understand you do not want to solo missions, but if them making the missions party only is gonna discourage players from doing it cause they can't find other players then NO it shouldn't be done. They can make the fights just as hard for solo as they can for party play.