I spent some time listening to the Kuzma last night and it really is a fantastic turntable. I'm starting to agree with the comments that it would be virtually impossible to improve on it without spending ridiculous amounts of money, and the turntables I have been considering are almost certainly not upgrades.
On further thought, I will keep the Kuzma and possibly add another - cheaper! - turntable/arm with a totally different character, such as a PTP Solid with maybe an Audiomods arm and a good MM cartridge.
Thanks for all the comments and suggestions.