The time to worry is when they remove the product off their products/pricing page. That happened to me just last month when they remove the Firewall Security Manager. Wasn't a happy day for me.
There are definitely plans for Virtualization Manager and the team has been hard at work on those. You can check out the WHAT WE'RE WORKING ON FOR VIRTUALIZATION MANAGER (UPDATED September 25, 2017) post to see the high level notation items the team it working towards delivering. I am glad to see you are a willing to test new release version. Can you message me your contact information and I will add you to the contact list for UX sessions and betas.