Totally half-baked idea here...
Ability mod is the only damage bonus that can “stack” within a single action. When present, it multiplies by the number of dice in the hit.
Multiple attacks in the same action always add dice to a final pool that is rolled together. A crit on an individual attack maximizes that die and other damage dice from outside the power (Hunter’s Quarry, Horned Helm, etc.) and adds crit dice. Multiple crits in the same action maximize more dice but don’t add bonus crit dice again.
Simple examples:
Ranger Dude attacks with Twin Strike and hits twice. He has a +1 weapon, Hunter’s Quarry, and no other damage adds. Since TS doesn’t include an ability mod, he deals 2[W]+1+Quarry damage.
Barbarian Dude hits with a five-die Rage Strike. He has a Strength mod of +5 and a +2 weapon. He deals 5[W] + 5*(Str mod) + 2 = 5[W]+27 damage.
Complicated examples:
Uber Ranger Dude attacks a prone target with a blistering six-attack combo benefiting from Headsman’s Chop, Hunter’s Quarry, and his +4 weapon, but no ability mod. He hits four times, including two crits. He rolls 2[W] damage and his bonus crit dice, and adds (maximized 2[W]) + (maximized Hunter’s Quarry) + 4 (enh) + 5 (Headsman’s Chop).
Frost Barbarian, with his Frost weapon and Lasting Frost, takes a double attack action that deals 2[W]+Str per hit, hitting both times and critting once. He rolls 2[W] damage and his bonus crit dice, and adds (maximized 2[W]) + (4 * Str mod) + (weapon enhancement). The enemy is now cold-vulnerable, so he uses an action point and uses the same power again, hitting twice. He rolls 4[W] damage and adds (4 * Str mod) + (weapon enhancement) + (cold vulnerability).
Ability mod is the only damage bonus that can “stack” within a single action. When present, it multiplies by the number of dice in the hit.
Multiple attacks in the same action always add dice to a final pool that is rolled together. A crit on an individual attack maximizes that die and other damage dice from outside the power (Hunter’s Quarry, Horned Helm, etc.) and adds crit dice. Multiple crits in the same action maximize more dice but don’t add bonus crit dice again.
Simple examples:
Ranger Dude attacks with Twin Strike and hits twice. He has a +1 weapon, Hunter’s Quarry, and no other damage adds. Since TS doesn’t include an ability mod, he deals 2[W]+1+Quarry damage.
Barbarian Dude hits with a five-die Rage Strike. He has a Strength mod of +5 and a +2 weapon. He deals 5[W] + 5*(Str mod) + 2 = 5[W]+27 damage.
Complicated examples:
Uber Ranger Dude attacks a prone target with a blistering six-attack combo benefiting from Headsman’s Chop, Hunter’s Quarry, and his +4 weapon, but no ability mod. He hits four times, including two crits. He rolls 2[W] damage and his bonus crit dice, and adds (maximized 2[W]) + (maximized Hunter’s Quarry) + 4 (enh) + 5 (Headsman’s Chop).
Frost Barbarian, with his Frost weapon and Lasting Frost, takes a double attack action that deals 2[W]+Str per hit, hitting both times and critting once. He rolls 2[W] damage and his bonus crit dice, and adds (maximized 2[W]) + (4 * Str mod) + (weapon enhancement). The enemy is now cold-vulnerable, so he uses an action point and uses the same power again, hitting twice. He rolls 4[W] damage and adds (4 * Str mod) + (weapon enhancement) + (cold vulnerability).