I host Kerio servers on DO as well as DNS and I've come across an issue. Going forward Kerio 8.2 will support DKIM finally however the keys it's generates are at least 400 characters long. DO only support up to 255 meaning I have to deploy my own DNS servers. Since I love the DNS interface on DO I don't really want to do that.
So I guess my suggestion is for DO to support txt records longer than 255 characters