VRAM might be an issue if the game was HD.
You have to remember that Diablo has very dated and small graphics compared to nowadays.
If you install it and take a look at it now, it's shit really...
If you are aiming at Diablo quality graphics then sure... VRAM not an issue. If you make looking at some HD stuff then you may end up with a problem.
TONKS doesn't even work on my MSI Wind anymore (in fact, long ago it stopped) since there is only like 128Mb of VRAM on it.
~Sol