I do believe regulation has greatly improved my 100 yard groups both on my .30 Flex and my .25 Marauder.
It would be great to have both worlds (regulated/un-regulated) in one gun that can be switched on or off by the turn of "something".
It's not in our nature as airgunners to un-do what we worked hard and long to get "right" just to see.
Once you do all the work to install the regulator (and in some cases modify the tube), get the tuneup/mods just right, and get the regulated version running right....really aren't going to (or aren't able) to un-do all of that to give a even chance to unregulated.