Also, I got stats from OP.gg.
I'm looking at OP.gg right now. Diamond League. Last 7 days. Fiddlesticks third highest winrate. Master League: fifth highest winrate. Challenger is third highest winrate.
I think the problem is that you are looking at daily win rates instead of weekly or monthly. You can't do that. The sample size is way, way too low to draw any meaningful conclusions. There are literally 5 games played for some of those champions. You can not draw any conclusions from 5 games. Look at weekly or monthly. Hell, you really shouldn't even be using Master of Challenger because even on the weekly measure, Fiddle only had 21 games played in Diamond, and fewer in Master. You can't get worthwhile statistical result from that low a sample. The 1,900 games this week in Diamond are a better measure to use (of course, they all say the same thing: Fiddle is in the top 5 win ratios).
Also, if you look at Elise (weekly, Diamond), she has a 44.07% win rate. She has the ninth lowest win rate. She's been down there for quite a while.
Look at the statistics again, and don't use the daily measure. That will give you much more accurate information. Fiddle is a top win rate champion. Again, by itself that doesn't mean much because win rates are not a great measure, but it should be noted accurately.
Fiddles only got popular when they fucked the jungle up to the point that people couldn't play other ones lol.
No, he was rising in popularity throughout the second half of season 4. He was a very strong jungle pick for quite a long time. His popularity isn't something extremely new. It has gone up a bit, but he has not risen from being a completely unplayed niche champion. He's been a moderately common ban for a while now (during the Rammus period, Fiddle was over a 10% ban rate at Plat and above.)