The parameter function is really awesome. But, a HUGE need that I would suggest is that the Custom Forms be able to recieve parameters from the url. One of the main reasons we haven't implemented PowerApps forms for our current customers is that it cannot recieve paramters from the url to be able to prepopulate fields in the form. I feel like this would be a great improvement and is much needed. I do love all that has been done already though and look forward to what PowerApps has in store for the future!