Agreed, Hallazeal was my favorite legendary back in the day, when healing cards weren't quite as common. I'd be happy with any of these cards, though I think Kalimos has some conflict of interest with the new Bru'Kan Hero Card.
With how powerful this set is looking though, I think Shudderwock would be a great powerful tool for Shaman to keep up, heck maybe even thrive on standard ladder again. I love Shaman, but goddamn the class is inconstant. They seem to want to want Shaman to win games with Bloodlust now that it's back in the core set, which is all well and good, but I think a control Shaman could also be viable with a late game powerhouse legendary. And again, the combo cards that made Shudderwock infinite are not currently in standard, so it could work.