Melee damage increase the number of stone you gather ... So pump weight et melee damage
Another tip : Put the doedicurus on a quetzal platform with ramp and weight is not a problem anymore ( except for the quetz )
On PS4 I tried to test it's obsidian gathering since it is "Rank 1", well all it was gathering was stone. So I went to another saying maybe something was wrong, NOPE it does not gather obsidian. Just use an Anklyo for that.