I like these ideas of yours the best. I think they could at least lessen the number of warm up pitches one gets. I'd hate to see a reliever get injured though because he's not warm. But I think the biggest thing is the pace of the pitches thrown. If you get a guy coming in and after the pitch he steps off the mound, wipes his head off, stares at the ground and thinks, then finally settles in before throwing it just takes forever. The clock will help the most.
Another thing to consider is replay. I like it but at the same time it takes forever right now. They either need to speed it up or even get rid of it. The game was fine before it was implemented.
They could also implement some sort of time out system where you get three mound visits per game. SS, C, Pitcher or the dugout can call for a mound visit.
Then during the playoffs all of the rules could get relaxed some.