My wish list as follows:
1. Handouts. My players love them. More is better. What I really like is access to a PDF download. Trying to put the book into a copier or retype a handout to give out is a pain. I like what Necromancer does with its product support page.
2. Monsters with a purpose. If you are going to take the time to create one, let's get it in to the adventure. I have tons (well at least 9 monster manuals from WotC, Necro, & Monte) of monsters with no homes.
3. Side/optional encounters that can be used as published or as part of the on going adventure. I do not like leading the players on, so I enjoy the 1 off enconters that I can throw at them, but still has the flavor of the overall campaign arc. Maybe even a secondary bad guy that could reappear later. Or a wandering monster encounter that has additional details and could be thrown in at any time.
4. Tie ins to the GameMastery modules. I love supporting stuff that can easily be linked into the campaign arc. One of the things I like about Ptolus is that there is plenty of support (tactical maps, adventures, art books, etc..)
5. I love the big leader type bad guy. The more history, the more interaction, the more flavor, the better. No wimpy bad guys. Leaders with dragons as mounts are the best! It does not get any better.
6. PrCs. Minimize the new ones, but make sure that they fill an important flavor element. I liked what WotC did with the Ravenloft PrC's, and I thought that it fit in well with the overall plot arc. Generic PrC's do not do much for me.
7. The new WotC format is a huge space hog. For really complicated encouters, it is nice. But for an orc hiding behind a tree near aroad, I think I can handle it with a short stat line and a page number where I can find the orc write up. Back in 1st edition, the A series (Slavers) had a couple of tactical maps that were part of the index. To be honest, I thought that was perfect. I thought that the Red Hand of Doom was a good example of how to lay out an adenture. I liked the tactical maps that were included in the back. I also like the map booklet that was included in City of the Spider Queen or being able to download a map booklet to print out is great.
8. Use the Tome of Horrors from Necro. They have 3 books full of monsters. Lots of good stuff.
9. Demons, Devils, 'loths & Dragons....oh my! I just can not get enough :)
10. Half role, half roll play, with lots of behind the scenes details to all DM's to fully flesh out the adventure. I like castles and dungeons with lots of background flavor. I think that is the reason most folks like the original Ravenloft castle.