Archer.
I can think of a load of really good reasons. Firstly the flat, flash style animation would be much easier for Telltale to animate, so we wouldn't get the occasionally dicey, glitching animation or mistimed expressions we do in their more ambitious translations.
Secondly, the game could do a great job playing off of what the audience want Archer to do, versus what he actually does. Most of the Telltale games limit how much of a dick you can be as the protagonist, whereas Archer is a dick by default - the player interaction could be more about trying to make Archer less of a dick, or by finding creative ways to be a malicious asshole. They kind of touched on this in Borderlands, and I'd like to see one of their games go all the way.
Thirdly, it would make the QTE action scenes more fun. If you fail a quick time event during, say, a shoot out, instead of it being an instant game over, Archer instead sustains a violent (and hilarious) injury that will persist throughout the fight. Deliberately letting the guy get more and more injuried, or skillfully trying to come through unscathed are both viable play styles that matches the humour of the show.
Fourthly. B plots. Archer flicks between spy thriller and office japes. I'd love to see a game handle that.
