Firstly I have completed VMA several times and have a few lightning and one Inferno (still after inferno sharpened). The fact that it is a solo instance and that there is lag makes no sense (yes I know why there is lag there). The fact is the solo instances should not rely on the servers they should be instanced locally on the client. The difficulty is fine just the added modifier of lag can make it near impossible to complete on some days and easy mode on others. Once the lag is fixed maybe even a hard mode?
Please see what you can do, I got frustrated last night and have been playing Skyrim on my X1. I play ESO on PS4.