I know it's an old topic, but nvm, I'd like to state my opinion.
I guess Toni is a cool protagonist. I don't prefer him over Tommy, CJ, and Vic, but he's still cool. Tbh, I don't see his relationship with Salvatore like 'ass-kisser', he just cares about staying in his rank (getting higher ranks as well) and earning money. As you can see later, after he saved Salvatore, he calls him 'Sal', but not 'boss', and he even talks with him like a friend later, but not a boss, and later on after he has been a made man again he became the right hand-man of Salvatore, and after the last mission of LCS he became a partner of him. "Hey we're both back. You and me!" - "Toni. We did it. We run things now. You and me."
(I guess he's allowed to do whatever Salvatore is allowed to, in the Leone family, except for things that affect Salvatore. However, he still respects Salvatore so much, maybe due to him being an old man, even if he was closely a partner/close friend of Toni.)
Toni's character wouldn't be as great as Tommy's, CJ's, and Vic's, I guess, but it's still tough and a real example of a criminal. Remember what he did to Casa? And what Fort Staunton got from him?