Hussar
Legend
How else would you affix horseshoes? To the top of the hoof? And, even if you did, what difference would it make? Since when does where you happen to nail a horseshoe in matter?There is no "screw over" or "nerf" happening here. Nothing in the language written says or implies that you just stick there with no need to balance. Now, if required ability checks to simply stay on while it is moving, that could be seen as a nerf.
Here's the thing. If an item grants an exception to common sense, it explicitly says it in the language. The broom doesn't say that it works how you want it to work, so it doesn't. You don't get to just add in stuff that isn't written. As written it isn't a combat item, it's just a transportation item.
Are you going to call it "screwing over" or a "nerf" if I tell a player that their Horseshoes of Speed won't work unless affixed to the bottom of the horse's hooves? Because it doesn't say bottom.
You feel that brooms should be limited, but boots are not. So. Okay. No one chooses brooms. They simply choose boots. Whoopee. You've managed to shift the players from one incredibly boring, insipid choice to an equally boring, insipid choice. I guess that a success?