I totally agree in regards to starting a SaaS onboarding process and ask for nothing. In fact I did that with a page builder I once built. Basically it dropped you right into the page building tool itself, so you could play and build a page. Then to save the page you just entered an email and password. It was excellent at converting into trial accounts. The platform had other problems and wasn't successful, but I was really proud of the painless onboarding process.