what might be happening is that CR is running the stored proc and then deciding which values to display in the dynamic part as it seems that CR won't show options that won't return a report.
Not using a stored proc, but joining to a table, if you have a cascading parameter, CR won't cascade down to combination that returns 0 records or display an option that return 0 records.
I've used lots of stored procs for reporting (ok, all my reports are store proc based) and I have used cascading parameters, but I usually use a Command Object to drive the parameter selection and it has been quick. My company has moved away from the Crystal Reports Parameters as it wasn't flexible enough, so it has been years since I used these features...
If I read your post correctly, you are selecting your parameter values from a view, I would have thought that would be fine, as it is akin to the Command Object.