For the individual player the Escape Plan is better than stock, and is OP in that regards. It makes the class stronger overall, but it does so in a way that introduces new skills: dodging minicrits and escaping with low HP whereas before you were p much dead below 40 HP as soldier. Adding more ways for players to get better at and improve the game makes the game separate levels of skill more and therefore more competitive which most people call good. As a weapon it is well designed because it makes the class more exciting, adds a new skill to master, and allows the player to interact with other players in interesting ways like rolling out. Its Overpowered but its still good for the player using because it makes the game more fun.
Holistically, the weapon doesn't disrupt the game flow and doesn't let individual soldiers control the game. It'd be hard to call it OP in the context of TF2 as a whole. The Escape Plan prevent soldiers from being relatively easy chipshot targets that can't maneuver or fight <50 HP. No one likes being killed, but fighting against a desperate EP soldier is more interesting than fighting against a desperate shovel soldier because he's more of a threat. It makes the game more exciting for both players because it removes a relatively free kill without completely removing the advantage the nonsoldier has. That makes it a good weapon for the game because everyone on the server has more fun because its in the game.
When you turn that individual lens to the booties you get what I said above: they don't make the game more interesting or exciting for the demoman because he's still just doing what he was doing originally. I think most people would agree that passive weapons are inherently less exciting than ones that are functionally different, and passives that don't provide interesting class expansion will always feel bland regardless of balance. The Razorback is relatively balanced but its not a weapon that is particularly fun to have equipped or fight against. The booties are similar. If everyone here agrees that they're not particularly fun or interesting to play with (as a player), then the discussion shifts to whether or not its worth having a boring but balanced unlock in the game because it makes the entire game more fun for everyone. I'd say fighting a demo with pipes is a lot more exciting than one that's a bit tankier and faster so its pretty clear on that count the booties don't work. I'm not sure if the booties are good for the game, but it seems they're not. They force both demos to use them, reducing the number of interesting 1v1s people can have with demos, and they don't really do much for the pacing of the game. If they allowed new pushes to be made or more exciting bombs to happen they might be worth keeping, but since they're really just a buff to the class with little substance, they should be banned