I don't know what full products I would like to see.
But I know what character options and expansions I'd like. Stick them in whatever product they most fit.
1: A character who can use shuriken in a manner that is actually useful. The best option for this in 3e was a Scout, and even then you took a big hit in effectiveness compared to just using a shortbow and spending a feat on quickdraw. I had a lot of fun with a houseruled, edited scout, but I'd like there to be an official option.
2: The Shadowcaster. Its odd that I like this guy so much considering that mechanically he embodies much of what I hate about 3e magic- per day abilities, tendency to nova with extreme effectiveness, then suck the rest of the day. But he was a triumph of theme, both in the "shadow" theme, and in the "creepy nega-magic from an alternate universe" theme.
3: The Hexblade. I could talk for a long time about what worked with the hexblade's design, and what didn't, but I'll spare you all.
4: Psions that aren't just wizard ripoffs. I want a psion to float above the ground and wreck things with his mind. I don't want a psion who casts fireball. Er, sorry, who casts spells almost functionally identical to fireballs, but with different names.
5: A swashbuckler/duelist type character. Historically that gets folded into the rogue. That didn't work quite right in 3e. Maybe it will work in 4e, but if not, I want a swashbuckler class.
6: The swordsage. Again, this is a melee class that actually had magic mixed into it in a way that was elegant and which didn't overshadow the "melee" part in terms of theme. Shadow Hand was especially nice.
7: A "magical girl" class. Fully anime styled. In 3e, this is actually the warlock class. In 4e, that may not be the case. If WOTC is too afraid to make a genuine magical girl, they can call it a warlock who has made a pact with celestials, or just a new class type that uses pact magic like a warlock, but pacts with good beings.
3e Warlock = magical girl.
Flies? Check.
Shoots rays of light at people? Check. They can even blind.
When wounded can recover her hit points and attack again? Check. Class feature.
High charisma? Check.
Fights with a sceptre? Check, though we call it a mace.