What I can say AFTER the buff.
Fiddlesticks is a shitty champion, and it's not a micro buff that is gonna do anything about it.
I used to main Fiddlesticks in D3, he is currently the most useless champ ever, zero damage, no escape AND squishy, can't clear the jungle properly, zero push power, worst last hitting, low ap ratios, the magic pen buff got removed it seems ?, no late game scaling, blue buff dependant, Zhonyas dependent, ultimate dependent...
Almost every mechanism in the game counters him (they probably design all the game features to counter him ?) : healing reductions, interrupts (stuns, etc.), knock ups, vision, dashs (you can just dash out of his ult and he's useless), tanks, QSS, mercury, Mikael's Crucible, Cleanse, etc.
Also, when you pick him, your team will often ask you if you're trolling and will just perform bad just because of the pick (a bit like if you picked Janna midlane).
Fiddle is nothing. Not a tank, not an ap carry, not an assassin, not a buffer, he can't even disable properly.
You need to be 1 full tier more skilled than the ennemy team to just have a chance to win a game (if you are plat 5, then you might win a gold 5 game).
Even Narkuss, a famous streamer, who used to be #1 Fiddle EUW (he used to be challenger with Fiddle all seasons), said that he was shit and he couldnt do anything with this champion.
Really, it's crazy that someone picked him in competitive, that was pure suicide, any pick would have been obviously FAR superior.