Only reason you need a sampler is if the internal sounds suck. Pretty happy with the ROM in my BK...

Tweaking... see above. The BK has most of the common synth tweaks, envelopes, filters, LFO controls. You need more than this, there's thousands of synth presets that go far beyond what the edits can do.

Look, I've got Kurzweil's, Korg synths, a ton of VSTi's... If I want to twiddle around programming sounds all day, no sweat. But when I go out on a gig, I'm there to PLAY. I want to sound like a live band, and I want to do it with the minimum of effort. I don't want an arranger so complicated it can do it all, because I've got plenty of other stuff that does it all. I want something that makes gigging EASY.