I'm With Stupid said:
There are so many situations where this will be difficult to do. How about the linesman wrongly calls offside when you're through on goal, the ref blows his whistle and everyone stops. The manager correctly challenges it. Now what? You can't exactly replicate a one-on-one with the keeper. And it's harsh to give a free kick or penalty when the other team has done nothing wrong.
There's no chance that technology would get rid of contentious decisions in football.
As an American who thought that replay would make worse the already seemingly endless sport of baseball, I must say it has worked remarkably well this season. With usually only a few minutes of down time per game.
It's silly to pretend football is "continuous", even though it's far more continuous than most (if not all) American sports. Injury stoppages must average four per match (maybe someone knows) and certainly there is time wasted for subs and for kick set-ups by keepers or free kicks. Bottom line is that the action stops for 15 seconds plus at least a dozen times a match I'd bet.
To me, it's bad offside calls that have the combination of the greatest impact on the game AND are the most "black and white".
Penalties and fouls are so often judgment calls, but if every offside call was subject to replay nearly all of the time replay will tell you the correct decision.
I know this seems silly, and it's off the top of my head, but what if a linesman carried two flags? He'd wave the red one on "obvious" offside calls. He'd almost always get these right. No replay. He'd wave the yellow flag on potential offside calls, on non-obvious plays that are "too close to call."
When the yellow flag is up, play continues until the team in attack loses possession or scores. When that happens, the replay is consulted and the proper call made. Managers would not be given an opportunity to challenge.
If you wanted to give a manager a challenge (and I probably wouldn't, but let's just say so for argument's sake), I'd have it restricted to goal kick vs corner kick calls, or touch line calls. One per match, and probably saved by nearly every manager until game end in a tight match when each possession matters more.