Two points for clarification:
1. Aquinas was never condemned by his bishop while he was alive. Kasper is probably referring to the condemnation of 1277, which was issued by Stephen Tempier, the bishop of Paris. Thomas had died 3 years earlier, in March 1274.
The story of this condemnation is rather involved, but the bottom line is that it doesn't mention Thomas by name, some of his teachings are likely included, and the bishop got some things wrong. St Albert the Great went to Paris at the time to defend Thomas from his detractors. Fr Torrell has a detailed discussion of this in his book on St. Thomas, (pp. 298-303). During his life, Thomas was certainly involved in disputes at the university, but his teaching was entirely orthodox.
2. On his deathbed Thomas said, “I have written and taught much about this very holy Body [ie. the Eucharist] and about the Holy Roman Church, to whose correction I expose and submit everything I have written.”
Thomas was a saint because he was humble. I don't see any statements like this coming from today's dissenting theologians. Until that happens, I don't see how they could really be compared to each other.