GP nerfs on the PBE right now
Meh is all I can say.
I agree with mana cost nerfs, but they put it on his seldom-used W which is really only going to nerf him in his already tough ranged matchups but won't really do shit when he's facing melees considering that its a lousy 10 mana nerf.
The barrel nerfs are kind of OK, but don't really fix the issue of sitting on a barrel all day long. I would have preferred 15/25/35/45/55 seconds per level. That way he would have a 15 second window to utilize a barrel he places down but in mid/late game it'd basically go back to live functionality. 40 seconds isn't going to be all that noticeable given how fast CDR can be stacked with even just first back.
Considering the fact that GP is basically the #1 top laner right now these nerfs are really tame.
The mana nerf should be on his Q, with maybe a compensatory mana return on kill to give him the incentive to use Q to farm and punish him when he tries to treat melees as gold pinatas.