If all champions' "effectiveness rate" (a value that is incalculable but it's like winrates plus intelligence) were between 49.9 and 50.1, and there was only one jungler with a 50.1 effectiveness rate, that jungler would have an overbearing first pick rate too.
There is ALWAYS going to be someone at the top. Always, always, always, always, always. There will ALWAYS be a #1. The question that is never asked when these kind of bitch threads come up is, is this #1 pick a problem? Being #1 is obviously not a problem by itself because there will always be a #1. So ask yourself (and post your findings if you come up with anything), what is the problem with Elise being first picked a lot? If Elise was nerfed out of the game (like she has been for the past two seasons) would there then be equal representation among all other junglers? Or would #2 simply get promoted?
Elise being the #1 pick is a statement. You have yet to post a problem. The description you allude to (early game jungler who falls off late) is matched by many champs who have similar power curves and mirrored by many others who are "allowed" to have ridiculous lategames when their early game is "bad" (and when these early games are perceived to not be bad enough, they are witchhunted relentlessly). Are you proposing that all (or any!) of Elise's wins would have been losses had she been disabled? If she isn't that much stronger than the #2 jungler that she's getting wins where she shouldn't be, the issue of which one gets picked more is mostly academic.
Barrels are fucking dumb, that's on point though- gp either knows how to barrel and wins or doesn't and flails uselessly then ragequits