How do I persuade my friends to switch to Mumble?

you wanted to say teamspeak right? right ?

This change actually has been out for a while, I've been on the layout for the past year or so. It's just recently they forced the existing user base onto it where before it was in opt-in, once you get used to the layout it's actually quite a bit better in my opinion it goes with the mobile flow a lot better, it's just getting used to it for the first week or so sucks. It's all so much better than their original redesign which had all of your servers on the bottom with your DM and you had to swipe back and forth between the servers to try to find it which was absolutely atrocious

That's easy. You have some 'product manager' or 'UX lead' who gets hired. They need to make a name for themself, and keeping the old thing going won't do that. So you get a big redesign. There might even be some QA testing to see if the new design is more intuitive. There will rarely if ever be any testing to see if whatever benefit the new design brings, is offset by making existing users relearn the whole thing.