Ovinomancer
No flips for you!
I looked at two CR 4 creatures in the MM. I'll check a few more. Maybe Chuul and Black Pudding aren't representative. Dodging, these creatures are getting critical hits in something like one in 400 attacks: you know that, right?
Are you looking for CR 4 creatures that are more or less representative of the DMG CR 4 guidelines? Why, when the guidelines are right there and you've already used them in this thread?
And you're now adding dodging to what the bladesinger has to do to survive in melee against CR appropriate creatures? When does the special pleading stop? The AC 18 fighter dodging significantly improves his chances as well and also doesn't die.
I have a high degree of respect with the thoroughness and rigor of your analysis on feats, which is why I'm so stumped as to why you're so strongly resisting this point.