I'm glad these changes are being made in a proper season setting. If the changes prove to be awful to play with then I look forward to being wronged and I have no problem admitting that it wasn't a good move.
Regardless we are at the point where we should try and experiment, we've had worse shit in ETF2L seasons before that didn't come down to a vote but just the admins decision. Was it shit? Yes. But it's only one season and these changes deserve to be given a long and thorough test as it could be a benefit towards a more entertaining playstyle of TF2.
The game is at the point now where we shouldn't give a shit on trying to attract new players, we've done that shit for years and it's done fuck all. What's important now is that we look for ways to make the current TF2 enjoyable to play and watch. There's also nothing wrong with just having a shakeup or a refresh of the meta every now and then. We have the abilitity to do just that and we should be more welcoming with experimental changes.
Having said all this, adding the gunboats always applies along with the med movespeed changes seems a bit excessive. I feel that both changes are quite significant as we are already going to make the medic role more punishing and having soldiers effectively more tanky in bombs feels like a bit of a double whammy.