Of course I am biased, but I still don't think Tom was a "bad" consiglieri. He made mistakes, but he was very good for the family at the stage of development they were in.

Tom did urge Vito to deal with Sollozzo.......it was Vito who didn't want to do business with him. Genco probably would have sensed more trouble by turning Sollozzo away, but Tom was right initially.

Tom was the first to get after Sonny, even though Sonny was uncontrollable. I get the sense he had to pick his battles with Sonny. I would have to concede Genco probably would have seen trouble with Carlo though.

Tom was the first to approve Mike's idea to wipe out a police captain and Sollozzo.

But here is why Tom made the Corleones what they were (and I give Vito all the credit): Tom was a lawyer with street smarts. Vito knew that as the families grew, the strongest would survive, but the smartest would prosper. I think that is why he advised Micheal to keep Tom around legally for the Vegas expansion.

Despite the Pentangelli thing, Tom kept Mike out of trouble with the Senate with the information he had. Tom made sure they had an ace in the hole with Geary. And whether Pentangelli was his fault or not, he found a way to silence him in the end.

All-in-all, I think Tom saw to it Micheal's plans were carried out like nobody else could. Genco was great for the streets, but Hagen was definitely the man for hearings, expansions, and legal protection for the family.

Maybe Micheal finally saw that with Hagen gone in Part III when he said he needed more lawyers and less tough guys.