I don't want to use parsers

[Allyrion]

And I agree information is a good thing. But to much of it is also bad - especially if it lacks context.

There can never be too much information. There can be UI clutter or server strain and that's why it might information can be overwhelming and a bad thing.
But not because having the information available is bad.

It can't be too much information and lack context. If it lacks context, then it's not really that much information.
Your enmity bars are actually a great example of bad, context-less information.
I'm not saying it's the worst thing to use it as a ghetto parser, but yea it's affected by other factors and breaks down with any target switching.

That is information that lacks context and it does little to help people improve.
Real parsers can, at the very least, give damage break downs by abilities and times cast as well as stuff like % crit. You should also be able to see damage taken by players and enemies and by who/what.
It can have death recaps.
Those are things that can help.
In the best case scenario, an enmity meter ends up doing the thing everyone that don't want parsers complain about - single out people that are severely underperforming with no information given on why that is, or how they can fix it.

I actually think SE could implement something like that because that's still nothing compared to a real logging site with graphs and positions. It's still enough information to get enough context and improve.
If not into the general UI, I just hope they open up add ons soon.
Though really that isn't my favourite solution since this is the only type of addon I want.

I have seen good summoners that were able to hold their own not epically high on the enmity bar but certainly more than 50% there.

A SMN with high enmity means they are probably blowing everyone else away in damage.