In his book Luciano is quoted in 1961 saying about Gambino...

"Someday Gambino will be head of the whole outfit in the United States."

This is another quote from the book

“Meyer said it wouldn’t surprise him if one of these days, Albert took care of the Manganos and took over that outfit. [In 1951, a year later, Philip Mangano was murdered and Vincent disappeared; Anastasia became the new boss.] When that happened, Carlo was liable to get very ambitious. So Lansky asked me to send a message back to Vito and Carlo to tell ’em I knew what they was doin’ and to cut it out immediately, that I wouldn’t sit still for Vito tryin’ to muscle in on Anastasia. I also sent back a little private side message to Gambino. I told him I thought he was one of the best leaders in New York and maybe in ten or fifteen years, he could be head of it all. But he oughta keep his pecker down and be patient. That helped put a clamp on Vito for a few more years.”

Although they were on opposite ends on that issue, Lucky had respect for Carlo. I heard this recently in a documentary and I believe it to be true, that Lucky's best talent was recognizing talent in other people and using that not only to benefit himself but to everyone involved.