Let's start by assuming that, one way or another, nearly anything is possible in StarCraft 2 Map Making.

Now we set our limits incredibly high, let's hear some idea's as to what we'd like to make.

Then the final step is, let's agree to make the plans to perhaps the next best AoS map, the next best RPG or even the next best defense map.

To keep this neat, follow a basic template.

Game Type: RPG, Defense, AoS, Bound, Arena, etc...
Idea's: Anything you think would make a good map of your chosen game type.

I think, you are contradicting yourself by limiting your game types to types within BW, which are mostly heavily outdated which puts your statement 'limits incredibly high' in a contradictory position.
These in my opinion are very outdated classification. AoS, Defense, Bound, and Arena could simply fit into 'Arcade' where there could be board games, card games, 'galaga', mario, etcetc. RPGs could have its own genre, FPS, TPS, RTS, Turn based games. I don't know if Simulation types will become possible though. Like simulating fighters, spaceships, or battleships, etcetc.

I'd really love a fleet type RTS, I'd also like to make one my self. I am sorta hoping for custom terrain sets. The only thing that'd be limiting should be the engine itself. Nothing more.
I'd also love Scrabble.

Assuming nearly anything is possible, Hentai Dating sim some turn based game like FF:Tactics except instead old school magic and swords it would include Plasma and Cyber demons. DooM turn based probably... yea.. and "You will be kill by demons"

Perhaps someone will go so far as to create the "Starcraft Board Game" for SC2. If anyone here has seen the trailer, or played it, then they know that in the board game, several battles take place over several planets, this would be rather neat to implement, say, having 6 different players (each a different faction for P/T/Z) fighting over separate sections of the Galaxy, to see who can: A - control the most planets after a preset amount of time, B - Completely destroy everyone else, everywhere, C - Successfully team up on everyone else to eliminate them first, etc.
A map similar to what I just described would be... actually, I'm gonna add that to my small list of maps to make for SC2. I hope the editor is at least a little noob-friendly... I don't want to be scared to death of it like the WCIII editor.

I am not being contradicting in a single way. Perhaps I only care for these types? The limitations of SC2 are not dependant on what I list here, so in the area's I list, the limitations are still starcraft 2's limits. Now back on topic, and stop being asses. Let's hear idea's and not bitches.

I do wonder if multiple planetary, like as in landable and completely spheric planet maps are possible. That would be incredulously awesome. Way beyond my expectations.

MTG: Magus /w deck customization, and all spells grafted to the planeswalker

Oh man, I've been planning a map for SC2 for a long time (because SC1 limitations are lame like that). A game entitled Space Pirates. You guessed it, you fly around in a spaceship as a pirate. Only more to it. Take Build-A-Ship Workshop and increase its customization to epic proportions. Throw in dynamic missions/world and complete sandbox freedom.

It is a RPG/RTS/FPS. I'm really planning to go nuts with it.

Game type: RPG/arcade
Ideas:assuming the map size can be anything? I'd make a 1024x1024 RPG that is all about a zergling running for his dear life from infested terrans! (7p, 1c map) It wouldn't be run zergling run, it'd be better and RPG style.

I've been planning and planning ever since the "Uberlisk" came out.
The ability to create new units inspired me so.

Game type: Campaign/Starcraft RTS
Ideas: You are Zerg, and there are many neutral units. By infesting them and altering genetics, you create new units.

I hope SC2 is as unlimited as it says it is.

Racing game, resident evil game with fixed cameras like in the games, temple siege 2 with UU and a team perhaps.

I would love to create Itero in a RTS format.

Yes.

@Marine - Map Limit is 256 by 256, this may seem bigger / smaller than SC1 depending on how big 1 by 1 is, in comparison.

Also, scaling is more than likely possible, so a 256 by 256 map with units scaled to 25% would essentially be 1024 by 1024, however only because of how big the terrain would feel.

I am thinking of perhaps making an RPG with a real story, history and quest, not just your average: anon hero saving anon item from anon villain.

Scaling units was in wc3. My only concern is whether or not you can scale terrains.

Which is why I explained to Marine he could scale.

You know what'd be fun.

Game Type: Bound/Run
Idea: Scaling lings to 1/5 their size, whacking first person on and making them run from a massive tauren marine or cyclops.
The size should make terrain look massive in First Person just to increase how insignificant you are.

I would probably try to push GTA further into SC.

What about pokemon guys D:

I've already got this entire campaign worked out with two custom made races. I've already finished making a tech tree and list of special abilities for the one race. It's this Zerg brood that got separated from the hivemind accidentally while investigating a Xel'Nagan artifact way back before they had even learned to evolve mutalisks. They developed on their own by trial and error forced mutations instead of assimilating others and have now returned to conquer.
The other race came from a lost Protoss tribe that was taken by the Xel'Nagan worldships when they left. They developed more powerful psionics but their technology is about the same as the original Protoss tech without dragoons. They follow a caste system where the leaders are determined through their psionic capabilities.

You could import models right? I think I'll make a Lylat Wars Campaign, there's got to be dozens of different units you could make for that

I'm pretty excited about what the editor can do. I wonder how big in size you could make the maps? Imagine a map on the scale of Fallout 3 (ok maybe thinking TOO big? xD). Still though a lot of ideas will hopefully work on this new editor.