To be fair, having Otogakure as a birth village hasn't caused an increase in clan activity. If anything, clan activity has been rather low and we have many inactive members. But there's been more village activity, which is a good thing.
But I also believe the open clan option would be a good thing to have. Though, I believe that instead of having a place where you can travel to any clan (like Jisegakure), there should be a different option when you travel to the halls that would be visitation or something similar. So if one were to be in Suna clan and wanted to visit Ame clan, they would select it and the clan leadership would get a request similar to a normal member joining where they would approve or deny the visit. That way cross-clan RP could be much more accessible instead of members having to quit one clan to join another.
As for who should get the village, I'm a bit torn. While Ame has been waiting longer, it's also been the subject for strife here in the forum. My own personal experience was not good either long ago, but maybe it has changed since then. I don't have any experience with Uzu, but I have heard that they're quite active. Of course, without looking myself I have no verification of it. While I believe both villages should have one and it doesn't seem like that'll be happening any time soon, my vote is swayed towards Uzu just because of my previous past experience with Ame. It's one of those tricky situations where no matter where you throw the stone, it's gonna hit someone.