Hi glentc,
Put simply, its a matter of priorities and where our customer base tells us we should focus - most customers we asked in the last couple of years said "Mac is more important to us" so we spent time and focused on bringing the Mac client into the SEPM. I suspect thats because for most customers, the Macs are in use by the big guys in the company, CIO, CTO, etc. and they want protection.
That said, we do see Linux as a priority and are working on our strategy at the moment to deliver full management of SEP for Linux in the future. As to when, nothing is set in stone at this point but it is abolutely in the works. To aid some of our customers short term problems of simply knowing whats happening with their Linux clients, we have released the reporting agent which you can see details of above. That allows a SAV for Linux client to send its logs and information to a SEPM and lets you report on the clients in the same way as your Mac and Windows devices.
On the VDI front, I'd be interested to hear your requirements here and what you would class as a viable solution - is there a specific feature of "VDI antivirus for VMware" that you are looking for? While other vendors have indeed released solutions, these use the premise of reducing security to increase performance. vShield from VMware is an awesome technology, but for us because we want to do so much more with it than just offload file scanning, its just not quite ready yet. We are working closely with VMware to develop the future of this technology, which would allow us to offload the majority of our protection stack.
Until that point comes however, we have made huge improvements with SEP 12.1 on virtual environments. Through using a combination of resource levelling, Virtual Image Exception and the Shared Insight Cache, we are seeing massive reductions in disk I/O and CPU usage on the virtual systems and the platforms they run. In some cases, we are seeing better performance with us than with a true "VDI Solution" - thats not from our testing, thats from some of our early BETA customers trying this stuff out in their own VDI environments. One customer in particular has seen an 80% reduction in disk I/O compared to SEP11 on the same platform (and better performance than a true VDI solution) - thats huge, and we aren't reducing security to do it! I urge you to take a look at this blog post here: https://www-secure.symantec.com/connect/blogs/configuring-sep-121-virtual-environments and try SEP12 out on your VDI infrastructure - I think you will be very surprised!
Please feel free to get in touch directly if you want to talk through any of this further, thanks!