One-back
 

What flaws would you overlook in a potential half-back if you were running a pass-heavy one-back offense, especially if you were scouting one for the draft? He probably needs to be a good pass blocker, but you also need him out in the flats, right? Maybe you don't need that top-end speed. He needs to make people miss, so you need elusiveness/agility. You don't really need the tough yards from him because you can have a third-and-short replacement, which means strength doesn't need to be top-end, or tough yardage yardage. Am I way off base?

You are pretty dead on actually, IMO.

In an SP career, I've been playing around with a "spread-only" offense (i.e.; shotgun formation for every play).

The bigger need is make sure that your QB has a high sense rush; you have good pass blocking lineman, and your RB can pickup blitz. If not, I learned quickly that you will frequently lead the league in sacks allowed.