They haven't said anything about more/better drops in HC, and honestly that wouldn't be a very hardcore move on their part. Since each person in co-op gets their own loot, 4 people means 4x the loot. Of course you would only be able to see your own loot but if you group up with people you trust they will likely give you anything that drops for them that you need.
No and no. The only difference in hardcore is that when you die, you stay dead. Multiplayer may generate more drops than solo, but only because monster health doesn't grow at the same rate as the damage potential of the group, so a well-coordinated group will kill a little faster.
edit: MF and GF are averaged in groups as Othniel said, which I suppose is a "change."
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...and if you disagree with me, you're probably <insert random ad hominem attack here>.
Im just hoping I can be good geared when playing alone.
I dont want to play with others just because it drops better stuff.
Yes as team you get more loot but I dont want to share either. Thats why I want to solo and taste everything for myself
Don't worry, the entire game is soloable including Inferno. You'll actually be better off soloing Inferno if you know what you're doing, compared to four people doing Inferno who may not be as skilled as you.
The only item drop benefit from grouping is that maybe something good for you will drop for someone else, and they could give it to you. Otherwise the one and only way to get better gear to drop is by stacking Magic Find, as others have said.