Sorry, KVM does not cut it.
Most larger enterprises either use VmWare or smaller ones as well as larger ones are moving to Hyper-V for the reason that they get all from one hand.
THere is a seroius need for router / firewall appliances, not only because people use clusters of virtulaization machines that must be protected. A special edition or special licensing could possibly pay for this - I know I would gladly pay 100 USD more for a Hyper-V package that integrates fully native.
I hav one of those cases here. I run a Mikrotik based fabric - a couple of Mikrotik hardware all around. Now I am adding an external system and the price of adding Mikrotik hardware there would not be even funny (payment is about 400 USD per rack unit height - no, this is not "cheap run the mill hosting" and it is not even the highest tier - in the highest offer there I would pay 1500 USD per rack unit). As I run a lot of Hyper-V (plus later a bare metal machine) I would really like just have a small RouterOS instance, especially as it does realtively little traffic (tying this into our fabric for control, some remote desktops, some internal dashboards, sql transfer traffic and maintenance - but not thousands of users, we talk of like 5 users maximum).
The abandonment of Xen has left RouterOS with KVM only, and that is not going to establish it as virtual router... which is market. SImply because no proepr company will decide their virtualization platform based on the requirements of a mere firewall, and will be reluctant to add another platform (the cost would be too high - in our case I would need a KVM specialist 24/6 and that will cost).
Readding support would open a significant market. Given that Mikrotik seems to move up from small devices only (i like the 36 core one - may get one myself for the cluster we build in the office) support for a virtualized environment may be another plus point.