To make it better, he will need and upgrade, like you said 50k rune ...
And thats only if we wanna make it able to absorb 1 hit...
things are so inflated on EZ its hard to make RoA useful without completely making you invincible outside of T3/T4
I have my RoA 100, and find it useful in zones like Qvic and such still... but making it like say... 100k (2ish hits in T3/T4)... it makes you nearly unkillable in those zones. especially with the reuse time only moderate. say a warrior has 80k + 100k rune.... pulls mobs in Qvic, it takes a few rounds to break through and start hitting HP. a couple more rounds, click the rune, HP regens back to full, rune breaks, few hits, reuse.
Makes it much much easier in cases like that. So for RoA idk what would be good for it. all i know is 10k rune is LOL