I agree about Howarth, who was an excellent broadcaster without sounding like a homer. Never was a fan of Joe Garagiola, who was often locked in his own world of "today's baseball players are nowhere near as good as they were when I played."
A name I would have liked to see was Tony Kubek, who broadcast with Curt Gowdy for many years on NBC's Game of the Week. He also worked for CTV doing Blue Jays games in the early years of the franchise before heading to New York to broadcast Yankees' games. He clashed frequently with George Steinbrenner and eventually left the game in 1994, saying he hated "the greed, the nastiness" of baseball at that time.