When using parametric constraints to transition between default template values and the desired value, a separate parametric constraint is often required to control the transition length. (ex. Default to New, New to New, New to Default)
An optional length of transition (back & ahead separately) would be useful to save time and limit the number of constraints created.
1000% correct. In my opinion, this is the most often used case for Parametrics: Transition-Hold It-Transition back, which requires 3 separate constraints to be placed. As long as we're asking, could we also get the ability to copy that Parametric Constraint/Transition group once it's set up? That way when I'm a little further down the road and have a similar area, I don't have to reinvent the wheel. Just Copy, Paste, and Adjust.