Windows Server Update Services (WSUS) deprecation

DanielNiccoli I have been advocating this for long time. But finally gave up. I've once wrote a long letter bringing up all limitations point by point for SMB customers with WSUS, so all these not having the luxury of ConfigMgr (SCCM). It did not deal out Daniel. I helped customers with the transition Nir outlined and the costs were acceptable for most as we also aligned their licensing with the new circumstances if required. 
In fact we could prove better results with the new methods while bringing down operational costs (mostly labour). So yes, I agree with the point of improving WSUS. Yet it was never a fully integrated role into Windows Server. Too many external dependencies like IIS, Certs, Reporting Services, Database and what not. Compared to AD DS or other roles and features the setup was abolutely not straight forward.

"To be fair, you haven't invested in new capabilities or features win WSUS since 2012R2." 

Yes investments mostly stopped with 2012 R2.

There have been improvements but nothing in area of UX. Most of them were about the update stack, as Abbodi outlined, UUP or even ability to client OS Upgrades and some other minor stuff.