I think your point up the page about how the players' association would handle the proposal would be interesting. I think the salaries for prototypical DHs would go down. Like you say, you're not going to pay Nelson Cruz full freight if he's only going to get to 2 ABs on average. Maybe the players could be bought off with a couple more roster spots, but I don't think this would change pitcher usage. Pitch limits and "third-time through" mentality is now well ensconced and with the game turning increasingly toward power pitching, I don't see managers letting pitchers go deeper into games.
Which will continue to make the game more boring for the "average fan", and eventually drive attendance and overall interest down.
Not a big deal for the posters here that are so invested and that watch every night (regardless of how things are going), but the corresponding lack of action/scoring makes it tougher for the "average fan" to justify plunking down the cash it takes to go to the ballpark on a regular basis when there's not much to see.
There's a reason the other leagues have relaxed their rules when it comes to what helps teams score - pretty tough to fill the stands when you're running the ball off-tackle 60% of the time regardless of whether you're winning or not.
Serious question - have pitch limits kept Fried and Soroka in the rotation?