I hear what your saying. I had the D's set up on in a room that was 13" x 19", they were centered about 8-9' apart on the long wall and about 10" from the wall. Snell spikes installed. A low pile area carpet over a hardwood floor, two sofas, two chairs, a few small tables, plaster walls, and four or five windows. They're really not hard to place at all. I didn't fool around with them after this initial setup. The D's were amazing. I didn't (don't) want to hear anything better - I'm quite happy.
For a finished basement, I recently picked up a set of J/IV's. They blew me away. With their published Snell specs (48Hz to 20kHz +/- 2dB anechoic), I wasn't expecting much bass. Well, I'm not sure how they do it. The bass is incredible. I'd call them full range and slightly warm compared to the the very neutral Type D's. I do not believe there are any independent tests of this short-lived speaker model, but I'd say the bass is definitely usable to below 40Hz, maybe the mid 30's. After all, the J/IV cabinet isn't that small. It's a shame Snell didn't include how low a speaker went at -6dB, as many manufactures do today.
In the end, this may be why you're not happy with the EIII's, your J/IV's were very good performers. I wouldn't be surprised if their bass was as good or better than the EIII's. The speakers used similar drivers in similar sized boxes, but the J/IV's had nearly a decade edge on speaker design. Perhaps Snell was conservative with the published specifications to avoid losing Type E/IV and Type D sales - I'm just postulating... (If anyone can find a reveiw, please post a link.)
Also, consider another listen of the D's, I'm not the only one that loves them, see the reviews at audioreview.com -> http://www.audioreview.com/cat/speakers/floorstanding-speakers/snell-acoustics/type-div/PRD_121067_1594crx.aspx