"I had better much more drastic measures had been taken" is incorrect. You're right that "I would rather that much more ..." would be better, or it could have been written as "It would have been better if much more ...".
"of late" is used correctly. It means "recently" or "lately" - they mean the same thing.
Please note that I have changed your thread title. Titles should include some/all of the words/phrases you are querying.