I guess any instrumentalist with Chicago was always overshadowed by Terry Kath who became a legend even more via his untimely death. And then Chicago - unlike Blood, Sweat & Tears, who went the oppsosite way - dehorned, dumbed down and balladized their music over the years, losing the instrumental brawn they once undoubtedly had. Cetera, once he found out that people like to hear him sing ballads, was a guilty party in that. The Stone of Syssiphos album they could only bring out a decade and a half after its recording really showed a band straining at the AOR leash.
The guy who replaved Cetera as a bass player and lead vocalist is not doing a bad job IMHO, he sounds a bit more manly than Cetera who in large doses can give new meaning to the term whimp singing.