The fact that they said Public BETA's won't be made available until late-June it seems like we might be seeing BETA1 and BETA2, and perhaps even BETA3 before its being made available for public testing so I would as always expect things to be rather messy with the first few developer beta releases of a new major OS version.
I have never had a great experience with BETA1 and BETA2 of new iOS releases, ever. But as the list of new features is so slim compared to previous releases just goes to show that the focus is 90% of performance and stability so one would thing that might resolve into a more stable BETA1.