It's definitely a tough balance, and at the moment with the red card appeal process I think it's out of balance. I think you have to go one way or the other, and shouldn't hover in between. Right now a team does have a number of challenges (2 per season, which they have to post bond for, and are penalized if it is frivolous) that can be made defensively - but as explained above, it only fixes the next game suspension, not the 10 man punishment and its ultimate effect.
If we had a way to review during the game (using one of the 2 challenges per season), then a 10 man punishment could be avoided and everyone made whole. To your point, to complete that balance then teams would ideally be able to make an offensive challenge for a red card non-call the same way. I think if you keep it limited to 2 challenges per season just like it is now, but give it real time effect, then we might be closer to that balance.
Again, this is not something that a couple of workday procrastinators on a forum can solve overnight. It's going to take years of testing (going on now) and it will need to be FIFA that makes the ultimate decision for every league, but the fact is Garber and MLS are behind it 100%, and are willing to let us be the guinea pigs.