I wonder what the general reason is that no mainstream mixer really gets into altcoins. Any thoughts from anyone? It seems like it'd be a neat opportunity to differentiate yourself and offer a service to people beyond just the Bitcoin-focused community. And as the altcoin grows in traction, you'd grow with it.
First, can you name one altcoin that you think deserves to have a mixing service, I can't name one that has all the decentralized and widely supported by the whole Cryptocurrency community, although it's a good idea when you cover Bitcoin you cover the whole Cryptocurrency community, it's just right that Yomit focuses on Bitcoin because that's the only coin worth supporting.
I can mention to you many altcoins that can be mixed according to the blockchain protocol if it allows it, but the most common and used is Bitcoin. Then it will be useless to mix everything, as it can be converted into Bitcoin. There are many swap platforms (Instant exchanges) that do not require registration. Any altcoin can be converted into Bitcoin and then mixed using Mixer. Using altcoins that allow for more privacy or using Bitcoin Mixers are both ways to maintain privacy on the blockchain.