Agreed. If you considered on how much time you spent hunting for the repair items, Your suggested changes seems pretty reasonable to me.
However, I'd personally prefer that the Guardian Stone's HP to be higher than the Emperium. On RMS, Guardian Stone have : 120,000 HP where as Emperium have 68,430. It's almost double the Emperium HP.
I personally think it meant to be stronger than the Emperium. and I'd love to see it kept that way. ( So much for it called a "Guardian" Stone otherwise.)
In terms of people being unable to break the stones, I believe it's just a problem with strategies, not Mechanical problem. (Mainly.)
My suggestion would be 280 ~ 295m HP for the Guardian Stone. i.e It's having the Guardian Stone about 25% Stronger than Normal Emperium Instead of around 95% Stronger during today's Beta.
Thank you for reading.
p.n This was done through rough calculation and rough thinking. I apologize for any miss calculation, misunderstanding and any emotional feelings felt while reading this suggestion.