Probably not optimal if he could go back and redo from start. But sometimes “good enough” is good enough. Shifting tactics in the middle of a war, to the extent of completely changing your public persona, when a lot of the loyalty of your followers (and the fear that keeps bystanders uninvolved) depends intimately on your existing persona, would not be easy at all.
Look at results, though. Until whatever it was happened ten years ago, Voldemort was winning the war with those tactics.
Modulo Harry, those tactics were good enough – no doubt about that. But were they optimal?
Probably not optimal if he could go back and redo from start. But sometimes “good enough” is good enough. Shifting tactics in the middle of a war, to the extent of completely changing your public persona, when a lot of the loyalty of your followers (and the fear that keeps bystanders uninvolved) depends intimately on your existing persona, would not be easy at all.