Yes, they discontinued the butler service around the first of 2001. None available whatsoever any more in any suite category. Just before the change went into effect, the Hotel Manager on Crown Princess told me that the reason for dropping them was they got a LOT of complaints from passengers about having another person to tip! According to him, the biggest complainers were the passengers who'd been upgraded to suites. Go figure!!!
I never found any particular use for the butler that our regular cabin steward couldn't/wouldn't accomplish for us. For us, it was of no real interest or value....and believe me, we like our comforts and spoiling.
Actually we were in the top suite back-to-backs several times on both Princess and Celebrity. IMO, the butlers on both Princess and Celebrity for the top suites, were superfulous....a good steward can and does do anything we have ever required.