There is a simple solution to replacing the Web Client and it gives you everything you need and more!
Unity3D... While yes this is a game development platform it can and is absolutely used to develop professional grade applications.
Consider this -
Developed in Unity a Web Client alternative would be developed in C#:
Available for the following platforms to be deployed straight from Unity -
No plugin needed web player.
Mac
Windows
Linux
iOS devices
Android devices
And more if necessary. Heck, if you really wanted, you could deploy it to a gaming console and manage your VMware from your couch using your Xbox, or PS4, or whatever.
The point is... Unity is a very solid platform for this kind of tool, always has been, and now with Unity 5 coming out around the corner VMware could develop something, in short order, that would be both stable, fast, and effective.
Take care!