My beef with Monopoly is that my family lets us do any sort of trades, so I pull crap like 'I'll give you $x and these properties if you refuse to trade with player X for the rest of the game.' If you're going to invest time in a game that takes as long as four player Monopoly, why not play something strategic and fun?
Considering that trading is the cornerstone of the game, I'm not sure why that's a problem? The big question is if that kind of trade is enforceable. I'd have to review the rules—and maybe they don't cover this—but I get the feeling that future events are not enforceable. You can promise not to trade with someone in the future, but nothing stops you from doing so. But I may be mixing that up with other trade rules.
How long does your four-player Monopoly take? The game can typically be completed within 90 minutes. In fact, tournament rules state that rounds are 90 minutes with the winner being the person with the most assets if it's not resolved in 90 minutes. When I ran the tournament, most games were completed within that time.
Of course, if it's a casual family atmosphere, then the game can take longer, but that's going to happen regardless of the game, especially if you go with something strategic.
Unrelated, I've once or twice played a variance of monopoly with a newly defined set of cards to replace the event cards, which you can take on your hand and play to do various stuff, mostly harm other players. Also slightly changed rules so that you get a lot more of them. It was super fun.
Having playable cards could cut down on some of the dumb luck. And if they're hoardable, then landing on Chance/Community Chest would actually be a good thing as opposed to the current, "Oh please, oh please, don't suck."
I would create a couple copies of an open Jail card. "Send one player to jail, or release one player from jail. Play before dice are rolled." So early in the game, you can send someone else to jail so he can't get properties or release yourself. Later in the game, you can send yourself to jail or release someone so he can face your orange and red gauntlet.