Has the suicidal squad mate AI behavior on higher difficulties been fixed?

On Insanity mode the AI actually seems stupider, and does not have much sense of self-preservation, though I wouldn't call them actively suicidal. The AI will simply sit on an active grenade and let themselves die, they'll ignore an enemy bum-rushing our cover. They don't seem to get that they're about to die.

The AI also largely ignores their own powers; I often have to manually order my squad to use powers on roit shield targets, which they often happily ignore.

However, they are not suicidal in that they won't actively attempt to bum rush enemies and get themselves killed, but they seem very content to sit still and not use many powers or bullets. Yes, micromanaging is often necessary to keep them alive, and yes, they're going to spend a lot of time "dead" if you don't play a very good game on Insanity. But if you take charge in the battle and leave them behind they generally won't go out of their way to get killed.

To this I respond with a passionate NO.

NO for people who don't want the long version.

I'm on hardcore for my first play through the game and I generally find that if I don't manage my squad fairly closely that they die against most large mob packs. I'm an infiltrator though, so it's not so bad, I just stay back and cloak around as needed.

But overall I can not say more emphatically there seem to be no noticeable improvements to squad AI, or if there are, they don't come close to the improvements to enemy AI. Giving Bioware some of the benefit of the doubt I do think that's true too. It's much harder to snipe in 3 than it was in 2. Targets move and strafe much more erratically.

EDIT: I want to change my response on this because I've noticed some interesting quirks. Against some of the more brainless enemies like husks, team AI has been stellar. Against Cerberus strike teams though, they usually go down pretty quickly.