My two cents worth!

Brothers, all sentiments aside....

I reckon the brothers loved each other but it is the business they had chosen

I don't believe Michael blamed Tom for the Corleone's misfortunes

Michael's comment to Kay at Connie's wedding "He's a good lawyer. Not a Sicilian but I think he's gonna be consiglieri" was long before Vito getting shot, Sonny's murder

I agree if not for Michael, Vito would have been killed by Sollozzo, with Police Captain McCluskey letting it happen

Sonny agreed to Tom's advocacy to waiting and it appeared so did the most experienced Clemenza and Tessio too
It doesn't constitute to me, negative opinion of Tom as I reckon it was all about Michael being the better strategist

I reckon Michael would have resented anyone mapping out his future, in that flashback scene at the end of II

No doubt Turnbull
Originally Posted by Turnbull
Tom wasn't Sicilian, so he didn't fully understand a Sicilian's overarching need for honor and vengeance against all logic. And, as a lawyer, he was oriented toward conciliation and negotiation, not toward force

Vito was slipping If anybody is to be blamed, first and foremost, it is Vito for appointing Tom as consiglieri
Michael's concern was justified and in times, detrimental too

Tom seemed clueless It was his sheer incompetence "Duh-h-h, Tom!"