So I basically spent all day on the phone, taking care of getting a new HVAC unit purchased and set up to install tomorrow. So I basically spent all day on League too and I am on a ROLL. 10 games today and I won 9 of them, including 5 straight with Jungle Trundle to finish the day. 6-0-3, 10-4-20, 5-3-12, etc... he is really legit. I wasn't that impressed at first, but I really found a rhythm with him. I build him just like Olaf (Wriggles, Zerks, Mallet, BVeil, Omen, Atmas), except I substitute in Mercs if the team is CC heavy, since he doesn't get Olaf's ult for CC mitigation.
Ganking with him is all about placing your W/E properly. Once you pick your target, you have to cut them off with E where you think their most likely avenue of escape is. It's great if you can do this in the brush, since it forces them out into the open. Place W to get yourself ahead of them or to make sure you can stick to them when they are running. Generally you want to place this after Pillar, since you want to maximize the benefit on attack speed. Coupled with Red Buff/Mallet, you can stick right on top of them and burn them down. Seems simple enough but most of the Trundles I've seen so far do it wrong. They use W to get in on their target and use E right where they are standing, which is usually a waste.
Favorite trick I've figured out with him so far is to act like a real troll. Stick close to walls, creep in the jungles, hide in brush, etc and when the enemy team approaches, split them up with Pillar and then attack. Champs like Ashe, MF, Kennen, etc, will often come to the front for JUST a second to poke and if you can split them off from their team, or even split three of them off from the other two, you can ruin any plan they might have for teamfights.
Fun times.
Also, I hope there are no Anivia nerfs. She's great, but clearly not OP. More annoying than the potential of Riot nerfs is that people will start banning her in ranked, which means you can't ban the champs that are really more problematic. :/