This subject has a lot of potential to be a really fun community discussion. Personally, I love the nostalgia involved with bringing back some of those old bosses, but I know there are a lot more ideas out there.

So, lets hear 'em. What are your ideas for Nephalem Rifts, and/or Rift Guardians?

I was just catching up on all of the suggestions and ideas in this thread. The idea of a version of Kadala as a Rift Guardian is awesome, and I really like the thought of evil ghost Cain as a boss, too. Of course, there are plenty of other cool ideas in here, too, like special events, classic bosses, memorable areas from previous games, cross-franchise appearances from iconic characters.

I'll compile a big list of feedback and send it on up. Thanks, everyone!

I should note that right now these are just ideas I'm compiling, and this isn't any sort of guarantee that they'll be implemented. I don't want anyone to get the wrong idea that just because I happen to like an idea that it means it will (or even should) be implemented.

This is a very nice thread and I would love to hear your feedback on such 'leaderboards'. Right now I can see some options there that seem like a summary of a 'Rift run' as well.
With tiered Rifts and Seasons slated for patch 2.1- it would be great if you could share how you feel about potential rivalry in Rifts with those features in place and how would you see the 'leaderboards concept' taking these 2 features into account.

Apart from Diablo ladders I have also played a lot of StarCraft II and even Brood War back in the days and personally cannot wait to see how seasons/ladders will work out in Diablo III - there is definitely great potential for fun there if competition is your thing!

We're happy to see that you like Rifts and are interested in ways to make them even more entertaining in a competitive way!