I updated to 4K from basically the same setup you have, getting a Sony AX100 and a Gates housing. I'd never go back. The still captures alone are amazing, and the video (on a 4K monitor, of course) is incomparably better if I have all the settings right. The Gates housing has proved much more failure-resistant than the L&M ever was for me.
Having said that, the Sony setup is now two years old, and it does have a few shortcomings - white balance is tricky, and it needs a good manual shooter to run it for best results. And Sony (and maybe others) are about due to release newer models. When, and whether they will be housed are the big questions.
In your situation I think I'd wait a bit - maybe six months? Just to see what else becomes available.
My opinion, no-one else's!
EDIT: Moving to 4K also involves a lot more I forgot to mention: the PC needs more memory, more speed and more terabytes of storage. At 100mbps, older PCs can have a hernia and freeze up! If you already have this, good. If not, it's good to factor this cost into the mix.
- SwiftFF5 likes this