The light of the pro heads is 1000 times better( more beautiful) than your compact, flat, versions. We need to recover a proper exposed flash bulb with the improvement of a powerful led for modelling. Barebulb simply doesn’t work with your compact heads...sorry!
The B4 Air was/is an AMAZING unit and silly it went away (except when renting where they still enjoy quite a lot of use). The B1x and d2 are great, but do not come close to the endless options which a new B4 could open up. The new version could be;
a) smaller/lighter 1200w/s Pac
b) longer battery life
c) all the current bells and whistles like bluetooth, usb...
d) total weather sealing
I will always prefer using the Pro heads when they are an option (again, always want a round dome instead of flat... seems to be a theme here) and the B4 allowed the perfect blend of studio/location functionality. It also saves 1 sandbag for the stand when you mount the pack, more-better less gear. I literally would buy 2 pacs right now if they were available.
Many modifiers require the ProHead and Pack, keeping some from enjoying these great modifiers unique to Profoto. Having an updated ProHead that’s battery operated (packless) with the features of the B10 would round out the Monolight family.