I've never blanched in the microwave - if I blanch, it's boiling water and a metal sieve to put the veg into it and remove after a few minutes.
Where I'm going to eat the veg fairly soon, then I might not bother blanching. But longer than a couple of months, then I do plan to blanch.
Freezing is always on open trays, before putting into bags, to avoid clumping during freezing.
I have frozen kale; it was rather brittle and not the best after cooking, but better than losing it completely was my thought process. Perhaps commercial freezers do it much more quickly and thus effectively?