A game like that... http://www.nitrome.com/games/rubbletroublemoscow/index.html It is a demolition game.
I want a game that has tons of loot! I love searching for new armor or a new gun for my character and oh! It would be an rpg! Also some time travel! Throughout history of video games there have only been a few time travel games so time travel with a super awesome loot system like diablo or boarder lands would be awesome! Think of all the weapons and armor you can make by jumping into different time periods!
This. Make it free except you have to pay a one time two or three dollar fee in order to be ranked on the leader boards. Try to make an Outwitters style tournament.
A game like PATAPON. This has been my all-time favorite game EVER, even more than pokemon, zelda, and metroid. Seriously, a game like this would be an instabuy.
Oh, btw Jove, a game without a level-up system is a game that doesn't stay very long. Personally, i think numbers make the game addictive, getting that key player's attack from 20 all the way to 379 is a HUGE accomplishment, and a feeling i absolutely HAVE to share with friends. If you make a game, you it is imperative that you include a level up system. (nudge nudge... something that Patapon executed perfectly!)
I love fighting and strategy game. If you can make interesting game on both genre, I will definitely buy it.