I wasn't too actively supportive of characters in Brawl, I was pretty much content with whatever I got. The only character I really wanted was Wario, and he got in, so I was very pleased with that.
I did end up developing an interest in Lucas and Wolf, though, and while I didn't actively support him, I was familiar with R.O.B. and always had a soft spot for him since I played him in Mario Kart DS. I was really big on Sonic at first, as I was a raving Sonic nut at the time, though I moved on fairly quickly and pursued other interests.
For Smash 4, Palutena was at the top of my list, and everyone else was a great distance from that. I think my most-wanted list prior to the ESRB leak was:
1. Palutena
2. Wonder Red
3. Chrom (or Robin, I thought both had their merits; did not expect or support Lucina)
4. Professor Layton? It gets a bit vague around this part
5. An eclectic mix of miscellaneous characters I thought would be neat, e.g. Little Mac, Tingle, etc
I didn't get involved with support for the likes of Ridley and K. Rool until I joined Smashboards in the wake of the ESRB leak's release. Which is why I will say that the best thing we as a Kampaign can possibly do is educate: I was totally indifferent towards K. Rool as a character prior to stumbling into this thread, and now he's one of my most-wanted newcomers. We're doing a great job so far, and yet we can go even further and spread the word even more magnanimously - get people interested, get them involved, demonstrate what makes K. Rool a great character, let them know why we support him. I know that that will do more good for our Kampaign than anything short of him appearing in a new DK game.