Hyper, no, because you only apply critical damage to the initial dice. The vorpal description states you may reroll when the damage result for a die is maximized, the critical damage (auto max) is only applied to the initial "roll".
Losing the bulk of a level 30 epic weapon everytime you crit does not seem to be the intent, nor good game design. As Dlichen has pointed out, using 2d4 weapon will only increase the damage 50-60% on a crit using the vorpal properties.
If you do that then you acknowledge that a damage roll has taken place, in which max damage is applied for all variable effects, you can only add anything after stat if it is a damage roll.On a Crit Max the [W] add stat+feat+other
Losing the bulk of a level 30 epic weapon everytime you crit does not seem to be the intent, nor good game design. As Dlichen has pointed out, using 2d4 weapon will only increase the damage 50-60% on a crit using the vorpal properties.