I do not feel this zeta has much value. I personally have invested in this zeta, and I did not notice a large increase in survivability for Holdo.
By the time her protection is gone she's already been taunting for a couple of turns, and the likelihood of someone spamming foresight on Holdo before the enemy takes 2-3 turns to give her a heal and save her from an untimely death is rather minimal.
Even if she did get some foresight, it will only heal her for about half of a hit. She does need something like a heal zeta for certain because she is just too squishy for a tank (absurdly low armor being the big problem), but it should really regenerate protection for her at the cost of a zeta. Just a heal is more of an omega quality trait.
Does surviving one more enemy attack sound like it is worth a zeta to you? Because as things stand, 0 more attacks is the normal (since it's only a heal on foresight dodge), 1 more attack if you're lucky enough to get foresight on Holdo while she's taunting. 2-3 if you're amazingly lucky and the taunt drops right then and the enemy attacks everyone else with foresight immediately after.
If it was protection regen, it would be active for a lot more of the match and justify the zeta investment. With just a heal, it's a very lackluster zeta trait. I would go so far as to say that no heal zeta that doesn't include protection is worth it. Nihilus's is part of an ability that turns protection into health so even that supports what I am saying.
So that's my spiel. Please consider adding protection regeneration to Holdo's zeta because as it is, it isn't much of a zeta in practice, though it sounds good in theory.