A lot of the improvement in the BK soundset is a few drum kits called 'New Pop','New Folk'etc., which first made their appearance in the E80.
But quite a bit of the overall improvement comes from better mixing and EQ'ing the Parts, I believe. The kits seem to sit in the mix better. Some better, fatter basses than the stock ones help also. Mind you, I've got the SRX-07 card in my gig G70, and the basses on that are fabulous.
So although I have both, TBH I haven't really felt the need to have the BK at the gig. The integration and control on the G70 simply can't be bettered, certainly the lack of touch screen makes a lot of things easy to do on the G70, and makes them major chores on the BK, no matter how many screens you have.
Mind you, for gigging a mostly arranger show (something I don't currently do), it will be hard to resist the attraction of the Chord Sequencer, the newer styles and kits. I will miss the G70's action though. I just figure.... Roland, if you want to be BACK, let's have a REAL TOTL like you used to make! I would SERIOUSLY be into a BK engined G1000 cased arranger. Full Monty... 3 UPR, 2 LWR, Man Bass, the G800/1000/70 action. Throw in the CS, return the SMF Mark/Jumps, separate outs, some audio loop playback, heck, I'd pay the old TOTL price for one of THOSE!
I have a friend that will be getting one ASAP, so I'll get to try it as soon as it's out. Who knows? The right set of new features, the right price... I might sell my BK-7m and get one of these BK-9's.
LOL... but then again, maybe I should hold out for a module version of the BK-9! Wow! I'm salivating at the thought of a full BK-9m..!
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An arranger is just a tool. What matters is what you build with it..!