I don't see how making and promoting Chris was a mistake. Other than being an addict, he was loyal to Tony and the crew. Lest not forget that he was clean for a while after coming back from rehab. The only problems with Chris arose when he was either high or heard when Tony had gotten a blowjob from Adriana. Hell the guy gave up his fiance after finding out she turned States, and continued being loyal up until the day he died. I think aside from Sil and Bobby, assuming he stayed clean, he would've been a good boss after Tony either got whacked or sent to prison.
One of Tony's mistakes were whacking Jimmy, believing him to be the rat instead of Pussy. Another mistake was not giving Richie Aprile his piece of his action like he deserved once he got out of prison. In all fairness, whatever was Jackie's was also Richies, but Tony was so greedy, he didn't want to give any of that up, he wanted all the power and majority share of the profits, not to share with Richie. Had he'd just given Richie what he'd asked for, it would've prevented all of Richie's animosity toward Tony, which only came about after that sitdown in which Tony ruled against him, he would've never plotted against Tony with Junior, and Richie for damn sure would've been a better captain than fucking Paulie Walnuts who couldn't keep his mouth shut for a damn.
Another mistake was whacking his biggest earner, Ralph, over a damn horse, when he wasn't 100% sure that it was even Ralph who burned the freaking stable. Which I don't believe he did, Ralph was turning over a new leaf, he was growing out of the knucklehead he used to be, into a trustworthy part of Tony's criminal enterprise, which David Chase confirmed after the show ended. But Tony killed him, in part over the horse, and because I think he was becoming fearful of Ralph, people were beginning to like him, and seeing how much of an earner he was, he probably felt he'd grow higher in power than Tony, and NY would've preferred Ralph to Tony because of that as well.
However his biggest mistake, was turning his back on the guy that went to the bathroom at the diner.
I agree that if Chris could have stayed clean,he would have been Tony's most loyal and trusted guy.
As far as Ralphie,I think he did kill the horse for several reasons.
I think he felt humiliated in public when Tony squeezed the extra money out of him when Pie O My won her race.
Tony took his horse and his girl.
Tony got the benefits of Pie O My's winnings,but when there was a crisis,he had them call Ralph.
Ralph never liked Tony,but couldn't do anything to hurt him directly,so he pulled a cowardly act that was totally in character for him. However,this did not justify Tony killing him over it.
As far as Jimmy goes,I thought that the basement scene with Tony pretty much confirmed that he was snitching.
