I've heard the CD6 before and I didn't think it was overly lean with bass.
I'd hazard a guess that the Proacs are the main cause of the lean bass. From recent experience of older proacs they sound very similar to some custom made speakers I've just got, tight and lean, great on vocals but no weighty punch on lower frequencies
What other component sources do you have e.g turntable, tuner? Do these sound lean too?
To play safe, I'd test some other sources with the proacs to make sure you really want to change the CDP first.
I'm finding that my Rogers LS55's are very hard to beat they have fantastic bass weight and it's well controlled. I'm going to test some Spendor S6e's to see if there's any improvement.
I've got a Marantz CD17Mk2 KI and the main difference is detail. I tested the Arcam 192 too and again, like the CD17 it was more detailed than the CD6000 OSE predecessor. There wasn't much difference in bass weight, just more detail all round.
My mistake, I think I mixed shaxos up with another forum member. I dont know if he uses ProAcs, my apologies, but even if he does, they (Studios) are not bass light, simply fast and accurate given suitable partnering equipment and compared to some of the boom boxes out there. Anyway, to put things into perspective, I've recently listened to AVI's 9.1 which compared to anything I've ever heard, sound 'bass light'. After a while you'll realize it's there and if/when something bassy comes along, such as a plucked D/B, you hear it in no certain terms. I think I still use a sub with them but not immediately, as suggested by AJ of AVI.