Yes, former PM Cameron should have given the pay raises that he did. Pay raises are good for everyone, except for the company that is distributing them if they don't actually have the money. However, the "little guy" in this country deserves some recognition, as well as some compensation. So, yes he should have given the raises.
It is easy to look back and say that someone didn't deserve raises, but David Cameron did his job until very difficult circumstances. He balanced the threats of terror with general unrest amongst his people about staying as part of the EU. When someone goes above and beyond their job description, they should be rewarded.
Pay raises should not have been given under the circumstances of Great Britain leaving the European Union because it was not yet known what the situation would be if that were to happen. Precautions should have been taken. Pay raises should only be given when there is certainty about the future and security of the nation.
No, PM Cameron should not have given the pay raises that he did, because he only did that for political expediency. Cameron knew that if he gave those pay raises, that those people would be loyal to him and to his party. He was buying votes, and he should be chastised for that. He is a politician, just like every other politician.