Yesterday I got the Skylander Bash. I tried him out. I ended up choosing the rolling path because the tail swipe was already pretty good. Now, after choosing the rolling path, my Bash's rolling does 41 damage each time he hits an enemy.
The first upgrade on the rolling path is an upgrade that makes your roll attack do 25 damage. After that, there's an upgrade that makes your roll do 31 damage and you can roll through your enemy's attacks but you still get damaged by their attacks. The final upgrade on the rolling path makes your roll attack do 41 damage and it increases the speed of your roll and you turn HUGE while in your roll. After that there is a move that you need the soul gem for. It increases your armor amount but even if you choose the tail path, you still can do this move.
That's all the upgrades for the rolling path. Good-bye for now!