I've already contacted Roland about drivers for Win 10 and they told me they are on the way and they're just waiting on Roland JP to send them over. They expect it will be when the final release candidate comes out so no worries there.
I'll admit I've been looking at other options as far as an interface and controller go but the reality I've come to is that unless I'm going with a larger format controller, there is no need to upgrade because the VS-700c works beautifully. I'm only hoping that the software for it goes open source (I think it has already if I'm not mistaken) and that users who program continue to develop it to work with new versions of Sonar as they come out to take advantage of the changes.
Interface wise, I will likely upgrade but keep the 700r as a backup. It's not by any means a bad interface but I'd like to either get an Orion or a UAD interface if the new Intel boards running Skylake have good support for Thunderbolt on PC finally.