Parametric Patterns

Has anyone used the Pattern function to draw a template drawing which can then be
updated with different numbers of pattern instance?
I seem to remember there was an issue in SE3d (may have been resolved as I'm thinking
back to V17) where if you patterned in a sketch it couldn't be parametrically controlled
(e.g. 5 instances of the pattern is updated to 9 instances), but if it was a solidfeature
it could be updated (like teeth on a helical gear).
I guess SE2D is like the sketcher, as I can't seem to change the number of instances.
Is there a way around this?
A Fill command maybe?