My problem with the archetype is two issues:
Having played the UA version for quite a bit now, I can definitely agree that while it is powerful, that "slow to turn on" thing of the bonus actions is a bigger balancing factor than people realize. I also find it very odd that the Hill Giant rune is one of the strongest when they are by FAR the weakest and dumbest of the giants by a wide margin. I would have much rather they nerfed storm giant rune and possibly even the hill giant than make them level gated.
Second they completely left my main complaint unaddressed with the archetype, that there are too many competing reaction abilities in one archetype, especially when they all effectively accomplish the same thing: granting disadvantage or causing an attack to miss. It's also particularly odd that they felt that the 7th level feature had to be nerfed from an infinitely useable ac bonus of proficiency to what they changed it to, when the storm rune is that AND MORE of a full minute every short rest. Like how the hell did that make it out of the design room?
If anything the storm rune and the 7th level shield ability should be switched, or make the stone rune the 7th level ability. Don't get me wrong, I am loving this archetype in play, but my DM and I took one look at the changes, both said "well that was stupid", and are now trying to figure how to fix it.