Sorry but what do you mean high risk very high reward? I know he is high risk but he's getting the same reward as everybody else. If by high reward you mean he can kill multiple enemies then we know he isn't the only one.

This is a list of mages that can kill multiple targets from a distance with their ult.
Fiddlesticks Ult Range: 800 and Base Armor 11 (+3.5)

Lux Ult Range: 3000 and Base Armor 8 (+4)
Ziggs Ult Range: 5300 and Base Armor 12 (+3.3) (not sure if that range is accurate?)
Anivia Ult Range: 615 and Base Armor 10.5 (+4)
Xerath Ult Range: 900/1300 and Base Armor 12.6 (+3.4)
Veigar Ult Range: 650 and Base Armor 12.25 (+3.75)
Rumble Ult Range: 1700 and Base Armor 16 (+3.5)
Karthus Ult Range: Everyone and Base Armor 11 (+3.5)
Kennen Ult Range: 550 and Base Armor 14 (+3.75)

There are a few more but whatever.. Kennen is the only mage besides Fiddle that is inside his own ult. He has higher base armor and overtime armor.

Anivia has a similar ult to Fiddle but she is not inside it. She has slightly better armor overtime.

Fiddlesticks armor should be around what Kennen has and fix his drain damage + passive.
He is the highest risk mage because of his ult. With the same reward as any of the mages above. To top things off he doesn't have stable damage. 3 of his abilities do damage. Dark Wind is random damage. To land Drain you need to be fairly close so you are bound to take some heat just trying to. His ult is great damage but easily countered besides the one person that you fear. Not saying you can't get multiple kills. Just saying that you won't if you are playing ranked with people that know how to play.

Play Cho

Haha my only complaint about cho is his Rupture. Decrease cast time to 0.60 seconds from 0.65 seconds. It's pretty easy to doge for me.

he get counter jungled pretty easily. all you need is a little cc to shut his early game.

Of all those you mentioned, none of them can wait for their team to engage, then flash in with a very large AOE of damage + a fear on an ideal target, with a syphon on that same target, then hourglass when in danger, and while the hourglass is active, the damage continues. About the only mage with a similar destructive force is karth, now if only Fiddle had an aoe silence, then he would be perfect... oh yeah...

Srs, fiddle is fine. If he ever sees a dip in use it's just the tide changing. Champs ebb and flow in popularity, but fiddle really is fine as he is.

You forgot Morgana.

I think the only thing i would change for fiddle is being able to move while draining kinda like leblanc's chains or morgana's soul shackles... I think allowing that would fix any inherent squishiness fiddle has (albeit he's made of straw) perhaps buffing his armor a little to? honestly i haven't touched fiddle since like lvl 15 but he's still an interesting one to return to

I'm not only talking about his ult combo. People always jump to that conclusion. "Well his ult combo is deadly so yep looks like Fiddle is A' OKAY." His passive gives him away. Not much of an assassin or surprise then.. Not all players will have the gold for hourglass by the time they have their ult. The silence is nice if there's not a creep wave around. Otherwise it will stay between the creeps mostly.

I respect your opinion though. Thank you.

Well, fiddle has a lot of tools. He's more than just his ult.

He has great sustain. The longest non-ult cc in the game. A multi-target silence. And an ult with one of the highest base damages in the game and is AoE.

Saying fiddle is easy to shut down, isn't really true either. Stealing any jungler's red/blue early on is a huge detriment.

Knowing that fiddle is going to start blue every time makes him easier to invade for sure, but every mana using jungler starts blue typically... Amumu is considered one of the top, if not THE top rated jungler in the game. he has to start blue...

Udyr, is a ridiculously good jungler. He has to start blue.

Fiddle has good tools, the new items made him stronger, the jungle changes made him stronger.

I see no reason to go changing fiddle when he's already a viable pick...

Especially when you've got 50 champions in the game right now that aren't...

Fiddle becomes truly terrifying when you have a good "container," champ (Jarvan, Sona, Viktor, Veigar, etc) that lets you just E, R, Q, W, and win.

It is because of this that I mostly play him as a support (it's awesome, just go with it).