Runaan's does 1/4th the damage of a regular auto attack. If the ADC is focusing a non-champion, your team effectively has 75-100% damage reduction from the ADC during that period. That's massive. Furthermore, it's bronze mentality to mindlessly focus the ADC. If the ADC runs away, congratulations, they might as well be dead for the purposes of the teamfight, since they're not contributing at all.
Tibbers gets an AoE stun once, maybe, if Annie has her stun charged when she casts it. Daisy can have multiple AoE knockups in a fight. That's a massive threat, and your opponents are torn between two bad decisions; focus Daisy and get destroyed by you and your team, or focus your team and have Daisy interrupt you anyways.
You can't have some braindead formula for when you use your spells; that comes with actually understanding the situation you're in during the game and acting accordingly. That awareness comes with getting better at the game. You look for the proper openings to cast your spell, same as any other ability.
Lulu's cooldowns, at max rank, are, respectively: 7, 12, 10. Ivern's are: 12, 0.5 (charge system), and 8. What are you talking about?
Again, bronze mentality to mindlessly tunnel on the backline. Furthermore, hard CC that's tied to a targeted gap close for your entire team could not be anymore textbook hard engage.
Daisy can also gapclose with Ivern's Q. Ivern's E is one of the most powerful shields in the game, especially since it deals AoE damage and 70% slow. His W is one of the biggest new mechanics in the game. Ivern's power comes from knowing how to use him; of course there are going to be players that suck at him, he's a difficult champion with a ton of new mechanics. That's not Ivern being bad; that's players having no idea what to do with him. The solution is to get better at the game, not kneejerk buff Ivern.