The current Fiddlesticks changes on PBE are a bit weird. The rank 2 and 3 ultimate cooldown reductions are insane, and I think that will push mid Fiddlesticks over the top. The removal of bonus damage to minions on e really sucks for mid fiddlesticks, but proper usage of protobelt still gives the same instant waveclear so losing that doesn't balance out for how much shorter the ult cooldown is. This is also a straight buff to support Fiddlesticks, and a pretty huge one at that, so I'd expect support Fiddle to also become really strong after this.
I also don't think this will realistically do anything to make jungle fiddlesticks not terrible. Jungle fiddlesticks has two issues currently: he uses too much mana to clear and he clears too slowly. Lower cooldown and higher damage on e marginally speeds up his early clear (particularly on raptors and krugs), but I definitely don't think that's going to be enough to increase his win rate by 4-5%, especially when jungle Fiddle now has an even harder time of shoving lanes after ganking. If you want to buff jungle Fiddle you should probably buff the efficiency of putting points into drain as that will have the least impact to mid and support fiddle; reduce or remove the mana scaling per rank and possibly add either some sort of damage buff (bonus damage on first tick, bonus damage to monsters, just higher damage/rank) or a (partial) mana refund on unit kill to go along with the cooldown refresh allowing Fiddle to efficiently drain small monsters without running oom.
tl;dr these changes will make mid and support Fiddlesticks notably stronger, while jungle fiddle will be better but still bad. Instead of current changes jungle Fiddle buffs should make drain a better ability, as buffs to drain will not have secondary effects on other roles.