I would certainly be interested in this! I absolutely love fantasy (favourite genre really), so I would definitely up for that. I've never watched/played/read dot hack however it's something I've been interested in (my friend recommended SAO and I'm kind of like - Nope, no thank you). Really, I'm interested in all of the things you've suggested.
The three different worlds idea is certainly interesting because it would involve a reasonable amount of world creation and also if/when the smaller pairs meet up there could quite possibly be language barriers ect. and just tons of differences and confusion and stuff. Badly said, I know. Also there's the possibility of a pair of characters verging towards being more 'villains' than 'heroes.' Loads of options. Sorry, though, all my thoughts kind of suck at the moment

While everything is getting busy for me I'm also terribly bored and have been verging towards going to sleep very early because there is nothing much to do, what with one/two active roleplays. And character development... My all time love. Mostly. I've never had a roleplay long enough for it to happen but I did an RPG for about 6 sessions with a friend and the character I played had loads of development and now is my favourite character and, you know, I love characters who change. 

Anyway, this all sounds awesome. Sorry for the slightly rambling text post though!