Some of the ones I want (NEED!) should be on microworld to do list, hopefully coming in the next year, but there is several things that 6mm fantasy needs to make it come in to its own, and put 10mm to shame!
1)Monstrous mounts and monstrous creatures. There is plenty of 10mm stuff that fits, but I'd like to see a small scale dragon that doesn't look like its been made from plasticine!
2) Goblin archers! Microworld have night goblins, but Id like to see some regular archers for gobbos!
3) NOT-Chaos dwarves. The eureka 10mm chaos dwaves are excellent, and I'd like to see some one make them in 6mm so I can throw all my money at them!
4) 6mm attack dogs! I know they would be pretty small but really really need some decent looking woofs for two 6mm projects!
5) NOT-squigs in 6mm. Both for fantasy and for my space orcs on order from the trouble maker kickstarter!
6) Fantasy war machines. Baccus has some nice bolt thowers and chariots but I'd like to see something for the Posh elves that looks a little less ramshackle and a little more elegant!
7) Technologically advanced man-rats! I would absolutely sell my soul for a 6mm steampunkish rat man army!

fantasy scenery- buildings, walls, siege equipment, towers, statues, graveyards, huts, mountains, hills.... as long as its not made up of huge skulls!
9) deamons and monsters. Things such as plague knights, horrors, spawns, ents, trolls etc... More things to fit in with 6mm ranges to encourage less use of 10mm!
I have left off giants, as the two 40mm ones from copplestone are so bloody fantastic! Kyuss in chains mentioned them in a thread on another forum, and they are the first giants I have ever seen and actually liked.