Okay, let's see. Wellness is a good food, but cats can be allergic to the vegetables and fruits in it, and they can also have digestive problems from these ingredients.
I've also heard from a few people whose cats didn't have the right low pH on this food and consequently developed struvites.
None of this means that your cats can't do great on Wellness, so don't let this info scare you.
Felidae. God only knows why, some cats get UTIs on this food because for them it doesn't produce the right low pH.
It's an absolutely, totally individual thing, something to be aware of, but do NOT base your food choices on this info. Bad things can happen from any food.
I don't think Innova is better than Wellness, just different when you look at the ingredients.
I honestly don't know what would come closest to perfect, but I do know that some cats can't or won't eat the "perfect" food, whatever we think perfect may be. That's why it's good to offer several brands if health problems don't stand in the way of that.
As a general rule it's good to avoid colorings and other unnecessary ingredients because they can cause allergic reactions.
Fish can also cause health problems, so it's wise to avoid feeding fish every day, and it's also wise to feed small amounts only if and when we do.
I personally hate carrageenan because of the digestive problems it can cause, so for my cats, based on experience, I avoid foods with this thickener. (You will hear from many people I'm sure who haven't noticed any problems from it.)
If you have more questions, go ahead, feel free to ask.