I think this idea is worth testing out. It looks to me like people only really use mammoths when they are already winning anyway. They are rarely decisive, and this might give them a shot.
edit: this post gave me the kel I needed for an avatar! I made this one a while back and had it sitting on my desktop waiting for this moment.
[RA Balance] Mammoth Tank - Buffing speed
Speed buff 50, from 42