This prayer update totally sucks. You just ruined it. Ahrim with master wand can ice blitz 43, thru mage pray + full arma (300+ mage defence bonuses). Well done.. 
Ofc it can. It's a matter of how unlucky you are, with less unlucky the higher defense bonus/prayer you have
Prayer in PvP is supposed to be 60% damage reduction. You saying ice blitz is supposed to hit 72 without pray (obviously it doesn't)?
says right here it decreases by 40% (explanation, it is hit - (0.4* hit) = new hit) in pvp.
public static int decreaseForPlayer(int hit) {
hit -= hit * 0.4;
so either he is lying or the original hit was 72 indeed.
Edit: with my set i can only get up to 46 max hit w/ ice blitz (maxed magic armour with ahrims set). Ahrims effect only increases spell effects, not damage