He counters literally every melee champ in this game with his point and click fear
Not really. His fear is really annoying, but if you have any CC capable of interrupting channeled skills he'll get ~2 seconds of Drain damage out before being out of tricks, then he's stuck in melee range against a melee champion as a mage with whimpy auto-attacks. That doesn't usually end well for him, especially if the melee in question could build MR against him.
Also, his ult has a massive channel time where it can be interrupted, which significantly reduces his potency against melee champions in general. You can't use Fiddle's ult as a response, you can only use it when surprising people - which opens up significant weaknesses to being flanked and stabbed in the back, and, well, assassins are all about out-maneuvering their prey.
As for Fiddle in general - the biggest counter to him is ward coverage, as his ult essentially requires him to surprise opponents to be effective. With proper coverage you can see him coming and just disperse so he hits nobody with his ult, or you can even interrupt him while he's channeling it so he gets no flash and no damage at all.
Trying to 1v1 him with a marksman is a terrible idea though.
The one change I would make for fiddle, and this goes for other champions, is to stop allowing their ult to persist through the zonya's effect.
You do realize:
can all AoE nuke a team so hard they auto-win a team fight, but with significantly faster cast speeds and massive range, right? None of them have to actually build tanky items to survive long enough to do their job properly. Many of them apply hard CC in an AoE with their faster, longer ranged skill as well.
For Fiddlesticks to get the same type of team-fight impact where he can AoE nuke things, he physically has to throw himself in the middle of an enemy team. Which is quite possibly the dumbest strategy imaginable.
How would he even be viable if he couldn't combo his ult with Zhonya's?
