Re: Interest Check for a D&D / Pathfinder Game
1) It depends. A dungeon crawl is usually fun, but plot driven games can be fun as well. I'm not too fond of arena games, as those can quickly turn into "Who is the biggest min-maxer" fests. A game centered around a fleshed out metropolis with a lot of places for adventuring can provide a nice balance for just about any kind of character.
2) Mythic Rules are nifty. Starting off with a mythic level could be an interesting way to help craft a backstory, as you could detail what exactly the character has done to become mythic. Plus, there's some awesome abilities in there for just about any build or concept.
3) Gestalt is awesome. It has the potential to be abused, of course, but it can also lead to some rather well rounded characters, assuming the rest of the world is similarly beefed up.
4) Honestly, depending on the plot? This kind of thing could be left open. A greedy, Evil aligned mercernary could very well go on a quest alongside a Good aligned cleric, assuming the cleric's church is willing to pay for the merc's services, or there's a good chance of loot in the process of said quest. It's a risky proposition on the interwebs where you don't know how good people are going to be about keeping IC arguments from bleeding over to OOC, but it can result in some really fun roleplay moments.
5) High Magic. Low Magic can be interesting, but then the GM has to make sure to give the party ample ability to do things tactically so as to minimize the risk of getting injured. Low magic generally means that taking damage is a lot more serious than it ordinarily is, after all. That, and I've seen more than a few GMs use a low magic setting as an excuse for "OK, so you don't have any magic users, and almost no magic items, so now you gotta fight this really cool monster that's really magical and has a lot of DR that can only be overcome by magic! Isn't it a cool monster? This way you don't kill it in two rounds!"
6) Again, depends on the story. Pathfinder does a good job of making even low level characters feel like they're something, but at the same time, starting off with some levels under your belt can be a lot of fun. Around level 6 is generally a good place, in my opinion, since you can usually dip a toe into a prestige class by that point, but you're also not starting a game with enough firepower to turn Camelot back into a model before you've got a real grasp on who your character is.
7) I'm not all that picky. I find that the games I like best are more because I enjoyed playing with the GM and the other players, rather than it was any particular theme or format. As far as PC... like I said, I like flexibility. What that means depends on what role in the party my character needs to play.