Could these issues you have be caused by plugins you use?
In my case most of the crashes are somehow related to plugins, but I have to say it does not happen very often now after updating all of them.
Still it would be great if Cubase/Nuendo would continue to run, even if a plugin crashes. Just saves a lot of headache, time (and money in the end).
If you think the same, it would be great if you could support this FR by a vote:
Solution to crashes by plugins - Sandboxing (Crash protection) - Cubase - Steinberg Forums