I'm thinking the jungle itemization options will hurt him a bit and without the gold of a solo lane, ouch.
You also have to "Fight" for the gold in a sololane. That's not something that Fizz can do in every matchup while he is farming up some of the most expensive items in the game in order to be fully effective (BotRK or Gunblade, TF, Zhonyas).
Jungle is considerably safer from a "minimum gold" perspective, even if its maximum gold is a lot lower. And, again, he'll be brutalized by a lot of meta picks (that aren't Gnar). Lissandra, Irelia, Rumble, Renekton...
Even if you want to "Farm it out" against tank tops, you're better off playing Irelia, farming up, and then watching the other team cry because they don't have the damage to deal with you (which was exactly what happened in IEM with Maokai top versus Irelia over-and-over).
Jungle Fizz also has some cheaper builds: Devourer + Wits End gives him a lot of on-hit damage + AS, while also getting some MR. Duelist smite has some interesting options if you are looking to 1v1 people (and it does have the -% damage mitigation as well).
My opinion is, if you're already a Fizz Enthusiast, playing him toplane might be fine since you have enough experience you have out of outplay potential. If you're looking to learn a new champ toplane, Irelia would be a much better choice...
so on pbe, zilean is getting a rework. His timebomb now sticks on the ground and attaches to whatever it comes in contact with then detonates after a bit. If you put another bomb on that, it explodes immediately like normal, but now adds a stun.
My understanding is they are just making his Q into a skillshot.