Not anybody can do crucible, coz its long, and needs stuff prereq. Its even worse if 20+ lvls, imagine a crash at lvl 39, sounds bad. But ofc, for players who DO cruci, it ll surely be great to go down 20 more lvls!

I d really like some more items like key of the court of justice, blue organs, enchants, or even Soj, and by that i mean items that can drop anywhere.
The best drops are from randomness imo. Adding bosses with 3 items loottable is just not the same pleasure. (remember when u got a unique diadem on bnet (i mean bot-less), its great to drop something rare,at that moment ur just HAPPY). And HxC players could benefit from those items, as they just cant play frost fire or cow set.
If u define new loot tables for new areas, instead of only a boss, maybe it gets more thrilling, like when u did "pit" or "ancient tunnels", coz u knew u can maybe get good stuff in those area coz of iLVL. (i dont know if thats true or not, but i red u can drop cow queen set parts from any inf cow, well if that were true and cow queen wouldnt drop the parts, that would look like what i am trying to explain; a zone= a loot table with some exceptions = you wanna farm it for a good reason).

Someone posted about a challenge for each class, which i believe is a great idea. That would make all chars to be playable for a reason, coz having java + smiter = GG is kinda lame imo (not mentionning the OPness of ama bow)
I was a big fan of maps on Warcraft 3 (Enfo, tower def, hero def, castle def, etc). I wonder if it s possible to take ideas from those maps, for example:
4 players team ( items from standard chars OR only pre stuffed chars, with new items to grow during the map)
every body must defend a spot, at some point, players gather to def 2 spots, at some point kill a boss all together, or some bosses. I am just throwing an exemple, but i hope my point is clear.
One thing is sure, pvp or pvm, with non-standards char could be a lot of fun, getting out of the "classic" D2 bounderies.