Like I said a few other times around the place, ivern's W bonus is pisspoor awful.
Ivern does have a few issues:
His early rank CDS(rank 1-4) are too dam high, but I understand why, since they're testing a lot of things on ivern.
E, when daisy's up her hitbox may make you miscast it on her instead of an ally, a simple solution however is removing daisy from E targets and automatically give her a shield when ivern uses E(like annie's shield)
Lastly Daisy's AI is buggy that's fixable through bug fixes.(Also would be great if they decreased daisy's 3rd attack cast range by 150 units she does it too far away constantly)
But ivern's W, I love placing bushes but a personal AA-enhancement just doesn't work unless you can give it to allies like janna/nami/lulu or do multiple things with it such as sona/thresh(thresh's allows reason to focus on playmaking) he isn't a dps champ nor AAs enough to actually get value from it. Thus making W useless early game (I love bushes but it's more valuable to just ignore W until lvl 13 or when you feel baron/dragon sneaks are important). Also I don't agree with taking bushes early just cause there's a cait/reng/nid or other champs who can interact with bushes for more bonuses. They usually can get through the early game just fine without your bush and would only need it later on making W feel even more like an "ignore till lvl 13" skill.
What they could do is just give ivern innate increased range when in a bush/exiting a bush(If they only give the range increase when interacting with a bush ivern can keep his base MR+MR per level) but there needs to be a different bonus for ivern's W esp for his special bushes when allies are in them to actually be a valuable skill aside from bush placement.
People builds are one thing but ivern's misplaced W bonus is wrongfully encouraging it too when again he isn't a DPS champ, he can't do multiple things with it, he can't grant an ally it, nor is he innatey tanky nor AAs enough to get value out of it.
Sorry for the long post, I just feel like ivern's W bonus is more of a "filler" cause riot didn't want to give ivern normal power when they're already testing what if you could give your allies a dash, make bushes, or have a summon that repeatedly applied CC.