I really enjoy playing Ivern; he is one of my favorite go-to junglers as well as one of my favorite characters in League(I have a coffee mug with him on it :^) ), and I have honestly never had an issue with him. I think that if your team isn't playing their best and people get fed early and get into your jungle, then yes, playing Ivern is miserable because there isn't a whole lot you can do for farming, and your only use at that point is landing Q's and shielding allies and having Daisy be annoying, but that's about it.
When the game is relatively even though? I think it comes down to skill with the champion. You should always be invading at every opportunity, and ganking as you see fit. In solo queue, Ivern is a pretty risky pick, just because he has such a niche playstyle that a lot of players don't quite understand and that really hurts his gameplay. I can't tell you how many times I've landed Q's and my team mate didnt go in , simply because they didn't know it worked that way.
In team based play though? This guy is a gem to have. It really involves everyone being on the same page as you and knowing how you operate, both as a player and a champion.
I wouldn't mind him seeing a little more love, though. The bush drop range is lolzy at best; all I could think about is paradropping bushes from behind lane for a top Rengar or something and having him just leap to the enemy unexpectedly haha. i think he could get a small buff to the AA damage from being in bushes, and maybe giving Daisy a little bit of heath regen? Nothing excessive, but just something small over time so she doesn't immediately become useless after you use her to tank a tower or objective.
That's just my input. :)
Also, new IVERN SKIN PLEASE. Candy King is awesome, but I want another just to have it.