Hammond did a difficult job well. I would say the proof is that when he came to office the MOD had poor relations with HM Treasury and very little delegated authority to spend without HMT sign off. Today is has the highest level of delegated authority of department.
Hammond was never a 'people person' but those who worked with him saw he was passionate about supporting defence, he was very pro military but he couldnt stand sacred cows existing unless there was a really good reason for them. I think the opposition to him comes from areas where sacred cows were looked at and found to be wanting.
I am glad Fox isn't coming back - a great opposition politician, found very wanting indeed in the Great Offices of state and arguably well out of his depth.