Dennis, I believe your description of Roland's present arrangers is more accurate than mine...yep, probably more close to lower end of MOTL.
I still think the styles sounded more detailed on the BK-5 than I remembered them on the G-70 and on the more recently played GW-8 and Prelude, but that may have been just an improvement in the way the filters and EQ were setup on the BK-5.
I feel the same as you...updates, extra (and very well done) styles, Sampled (and Custom) Voices, and reasonably prompt OS upgrades are very nice to have (essential in the latter case) and it is cool to see companies (AJ at Ketron is doing it too) continue to support both for gratis and/or at a fairish cost.
I do remember when the first Roland E-series (made at the former SIEL synth plant in Italy) hit the market, back in the late 80's, and how they blew everyone away with, not only the newly developed LA (Linear Arithmetic) sounds, but the strength and musicality of the accompaniment patterns. Back then you got 4 or 5 extra styles on a ROM Card (8 on the Easy Eight card), that was fairly expensive for the few you got, but at least the styles were of equal quality as those on board.
I even bought a Roland Super Card for my E-70,
http://m.matrixsynth.com/2010/12/roland-super-card-msl-15.html which gave me a whopping 60 extra styles (it was all the then available Style Cards rolled into one unit) and it plugged into the E-70's card slot and required an AC adaptor...it even had a card slot so you could plug in any newer cards.
They were really ahead of the game, and murdered poor Yamaha (and everyone else) for many years, until the PSR-2700/1700 and the PSR-8000 finally let them catch up.
Now Roland's arranger selection is a mere shadow of what they used to make...kind of sad, really.
Ian