I too am down with the Femme Fatales, Heavy Snow Pirate, and Prequel episode ideas. The strength of Lost Planet is definitely in the Campaign mode and I'm sure that Capcom realizes this too.
As far as environments are concerned...
- Snow covered abandoned city being overrun by Akrid
- Jungle Jungle!
- Desert Mountains/Caves
- Another slick as snot NEVAC facilty like in Episode 4-3
- An Airship battle stage
As far as Over-G are concernced...
- A massive one like the sand worm from Episode 3 but the entire chapter takes place inside the body ala Gears of War 2
- A pair of flying Akrid
- A giant crab/lobster like Akrid
- An underwater Akrid
As far as new VSs and weapons are concerned...
- A rare VS that only works if you have a Battle Suit
- "Skates." Put them on like a battle suit but you essentially get to skate around but with half the health of the battle suit.
- A VS that acts like a really big shield. It only has one VS weapon attachment but it can hold other players while using this powerful shield
- Melee weapons! Capcom could have fun with this idea by throwing in Rebellion, the Z-Saber, A monster hunter blade, Small Chainsaw (dead rising), etc.
- Pistols as a standard option. Also include dual wielding Dante's Pistols. When you dual wield holding down the trigger will cause one of the guns to automatically fire on the nearest enemey and the other gun is free for you to aim.
- A big bad crossbow that pins regular soldiers to walls (if they are close enough). Won't kill them out right but it's great to trap someone with (unless they wiggle out of it).
- Mega Buster
As far as character parts and models are concerned...
- Cole Train and Baird. And when Gears of War 3 is closer to being realeased Anya and Jace.
- Chris , Sheva, Josh, Leon, Jill, Claire, etc.
- Dante and Nero.
- Cammy in her Cannon Spike get-up. Guile would be cool as well too.
- Nathan Drake
- Nathan 'Rad' Spencer