Yeah, I am very glad they evolved to the EE-3. The Supertrooper Blaster just doesn't do it for me. I love the white armor, but the blaster...I don't know. I think it's because the Uzi, I was familiar with before I ever saw the blaster. And the Uzi is pretty iconic in form. Bapty/ILM/Lucasfilm has done an immense job masking known weapons, but it's hard to hide an Uzi.
For reference, I did check some photos of the Supertrooper blaster, and it is based on an Uzi replica, with a Graflex top tube with telegraph key, what appears to be the same sweep arm base as the jetpack stabilizer as the muzzle (imho), as well as an additional non-jetpack stabilizer sweep arm base used as a greeb on the side of the blaster, as well as other greebs.
For you toy collectors, this is the blaster used for the Supertrooper which has been recently released as the Boba Fett with Prototype Armor in the 6" Hasbro Black Series that was only available in the U.S. at Walgreens. Not sure if the toy comes with this blaster or the EE-3, but it would make more sense to include this one obviously.
I believe the side greeb sweep arm base is a 4th variation to the three Transcriptors (J A Michell) Unisweep Sweep Arm Bases chronicled expertly by
Art Andrews at TDH. I ran across this possible fourth variation in a recent eBay auction. Originally it seemed that a "mid-height" base was used for this side greeb, but that would've required some cutting/lathing that may not have been necessary as the final form may have been available from a natural part.
This is derailing... Anyway, this blaster has the telegraph key and Graflex top tube (with the bunny ears, but no buttons or glass eye) as a "barrel shroud" on the Uzi replica and are all painted black.