I'd like to see a lot of what other have said:
1) more purpose to cell stage. have there be the change from single cell to colonial cell before creature.
2) more changes through each stage in creature.
3) add creature controls. offer a F1 to F12 icon system on top of the screen with the option of having ten creatures per group, along with ways to group creatures and give them commands. In creature, if you get a group, they follow you and mimic you: you attack, they attack, you socialize, they socialize, you're basically the little leader. Why can't you have slight control over their options. Say, if I want the Alphas attacked, but am tied up in a fight, I want my guys to go after the Alpha- I can handle myself. I can order them to do that.
4) In tribal stage. I'll finish this later. bye!
Edit: Now I'm back.
Okay, 4 again. In tribal stage you play as a creature in the tribe, leading your tribe and telling creatures what to do, but you're not in overview all the time. the ai can be really dumb sometimes and I'd like to lead my guys into the fight. The overview option is still open to those that like playing it that way and you have a way to transfer between each view at will.
5) In tribal stage can name little babies if you want to. You can also teach them stuff.
6) Back to creature quick- you can have several options to choose from in the command menu. Defend, attack, flee, hunt, follow me
7) Same choices in tribal stage, but this time you can tell them to heal someone by just pushing buttons instead of clicking. You can have different factions in your tribe, warriors, gatherers, and socializers.

You have more tribes to interact with instead of just the five or so that you get to now.
9) If you conqueor another tribe you can send a small group over there to inhabit that place and rebuild so you have more tribes and thus more people following your beliefs and choices.
10) the civ stage allows you to lead your people in fights, commandeering vehicles to shoot at enemy cities. Allows first-person view like in creature stage if you choose to do so.
11) space stage allows you to blow up stars and in doing so blow up the entire star system. You're also allowed to create your own technology like, say, stargates or starportals or something so it's easier to travel between systems. If you start at any stage, it'll ask you if you want to pollinate the galaxy or if you want to be thrown into a preexisting one where life already exists. It kind of annoys me when the spore.com page asks How will you create the Universe when you really don't- you just live in it. You should get the choice of starting out in an empty galaxy or starting in one where life has already happened.
12) in space stage you can go to other galaxies- more galaxies. Not meaning other players' games, I mean other galaxies within our own realities.
13) The complexity limits should be made larger for everything- adventures included. I'd like to have a huge full-scale war in some of my missions.
14) Adventure Creator should allow us to pretty much make our own behaviors as well.
15) If you download a mission, you automatically get the creations from it without having to play it in space stage or in quick play to download the adventure creations separately.
16) Have a plant editor so we can make our own plants.
17) In cell stage, can choose whether or not stay in water for creature stage or go onto land. If you choose water, then another stage is added where you're underwater for the creature stage. You get to befriend water creatures and die if you go onto land, whereas you die when you go too far into the water right now. Then the underwater tribal stage happens where your homes are reefs and the reef grows when you beat other water tribes. You also get an underwater plant editor. When you go to the civ stage, the reefs become city-like. You conqueor other cties and move into a amphibian stage where you go onto land for a little and build space craft. Then you go into the space stage.
1

throughout all stages have option of F1 to F12 lists where there can be ten same creatures in one grouping, allowing you to better control your comrades.
19) have a technology editor where you can make star drives, cloak devices, and shield generators and stuff like that. You can specify something from a pre-set up list or make your own effects.
20) Really, really HIGH complexity allowances. Can have lots of stuff more than what is already available.
That's it for now. I'll add more later.