Just FYI, I believe you are still confusing the various models. The original was the large, scooped, deep low end, sizzly top end HT210. Next, Jim came out with a much smaller 's' model, using the same tweeter and I believe the same drivers as the original HT210 as part of the modular HT322, called the 's' stack. Finally, he came out with the revision of the discontinued SA210, called the HS210, which has a much tighter, mid present voicing (hence the 'high sensitivity' name) and a totally different tweeter. He then added a neo cab with a somewhat similar design as the HS210, called the AE210 (NICE 210!)
These are best thought of as completely differently voiced cabs, versus 'updates' or different versions of an original cab. The only 210's currently in Jim's line are the very nice AE210 (neo) and the HS210 (the SA210 'update').
Based on my experience with the SWR GJr. III, which I continue to describe as one of the lamest 210's ever (love the GIII though), it blows my mind you would think the GJr. could keep up volume-wise with any of the four Berg 210 executions. Just IMO and IME, since I've played or owned all these cabs at one point!

I've never been able to 'fart out' either the HT210s or the HS210, but easily drove that GJr. III to beyond xmax and I think xlim or whatever (it farted in a big way with any sort of low end pumped into it, even at low volumes).
I will agree though that the original HT210 (which it seems it the one you owned) is among my least favorite 210's, and my least favorite Berg designs... way to much deep low end, way too heavy, not enough mid character or punch. That particular Berg craved a LOT of power, and if you weren't cranking a good 500+ watts into it, it could sound a bit anemic, which is possibly what you are describing. The current HS210 is a totally, completely different beast IMO and IME.