1) Is it really a random crit--or should that be, "is it a really random crit?"--when an item blows up? Random location (LL RL LA RA LH RH LE RE H N C A B [but NOT nerves]), random severity (1-9)?
Because with roughly the top half of the crit results on just over half of the locations being potentially lethal, says I should be anticipating about a one-in-four kill rate. I suspect I'm on the high side of that (3-in-a-row stone giants last night, for example) but I don't log sessions so I cannot GRep to confirm/refute.
Or does degree-of-failure play into crit severity? (I don't really think it does, because I've had poor crits on high end results, and death-crits on comparatively low ones.)

2) Is there any benefit to Lore (or any other skill/stat) in changing the area affected, or the severity of the crit? We know that Lore (and stunned status) affects the endroll required to get the explosion in the first place, but can we affect how efficacious the explosion is?