heres the fix for slow play
people who are slow need to just let the faster groups play through, and we need to create more forward tees and encourage people to use them
Everybody says "I'm not a slow player" then there should be no problems with slow play
but there is
When I take my annual trip to Florida I go out with my wife, my Father in Law, and my Grandfather in law. Let me put it simple, the three of them are absolute HACKS

My father in law shows some potential at the possibility of breaking 100 with a little bit of practice, and he and I play a lot together. He's not terribly long off the tee(average drive 150-160) and ok from tee to green, but all he does at the range is hit driver, he struggles with his iron play, and as for short game, forget it. I've seen him putt from one side of the green back to the other and then back again. He's improving but still has a few blow up holes
My wife just likes to go out and be out on the pretty golf course, wear a cute outfit, and most times won't even putt she'll just pick up in the fairway. She hates teeing off in front of people and if you added up all of her strokes plus penalties from improving her lie, her score is probably closer to 200 then 100
Then theres my Grandfather in law, has more money then he knows what to do with lives in Florida, but NEVER goes out and plays a real course unless we take him. He's older so his distance is almost non-existent, he has poor iron play since he still tries to hit 3 and 4 iron instead of fairway woods or hybrids, short game runs hot and cold and he can't adjust to the faster green speeds at the resort courses vs the greens at his retirement park where they just cut the grass really short. His problem is he'll hit 2-3 balls OB or into the rough, then he'll top or chunk 4-5 shots from the fairway, then blade a wedge over the green, chunk the next shot into the bunker, take 2 more to get on the dance floor, and then 3 or 4 putt. After each shot he'll offer up a long winded explanation of what he did wrong on each shot. The best is when he'll finally get it in the cup he'll look up at my wife who's doing the scoring and announce thats a 6
Now, I've been out on some 6 hour rounds with them, when a faster group comes behind we let them play though, I realize my group is slow. I do have to say that marshal's coming around and yelling doesn't really help anything. In fact it makes things worse because my grandfather in law is a stubborn SOB who thinks "I've paid my money to be out here on the course I can take as long as I like". Wrong attitude, but at 85 years old I'm not going to change it and neither is a marshal.
Now what WOULD help IMMENSELY is a forward set of tees. The three of them ALREADY play from the reds and they're still looking at 430 yard Par 5's, 315 yard par 4's and 140 yard par 3's and thats on Lake Buena Vista which is the second shortest course at WDW. The only one in that threesome who has any chance playing the reds successfully is my father in law. My wife and GF in law have NO chance, its going to take them at least 5 just to get to 100 yards on the par 5 and they're hitting DRIVER on the par 3's and still are short of the green.
My solution, create a forward tee box making par 5's 300-350 par 4's 200-260 and par 3's 80-130. My wife would play that in a heartbeat, she LOVES playing the par 3 courses around our house in NY because she's not intimidated by the length. And she'd drag her grandfather up to that tee(he wouldn't know the difference anyway) No forced carries. It would make life simpler for EVERYBODY involved.
lets face it the three of them are closer to the average golfer in this country then anyone on this board. I'm sure there are some on this board who would tell me that they just don't belong on a "real" course and should just stick to the par 3's. But that ignores the fact that the majority of golfers are being KILLED by the lengthening of courses, they don't have the distance to play 7000 yards.
Put a forward tee in and encourage people to use it, I almost GUARANTEE that round times will get shorter