The warp isn't just emotions anymore. Your description would have been accurate for the Realm of Souls days, but after the start of daemons and Chaos I don't think the warp would get better even if 40K went noblebright. While other parts of the warp are essentially free soul output, Chaos is...alive. Sentient as a whole being. It acts with intent within the warp to change it and itself, to preserve its own nature. That is why exposure to Chaos can cause corruption that carries over into the Materium.
That's not even getting into some of the ideas that pass around about the Deep Warp...
The description is right because whole warp is... "Collective Unconscious" of everything. And Chaos is the worst of emotions, the unimaginable pain, the most disgusting rape fantasies of those in Materium. Every little thought or emotion affects the Empyrean to some degree, most people can't do much to the warp on their own, but lots of people thinking similar thoughts or feeling similar things will have an pronounced effect. This is the reason why the Chaos Gods, are well, chaotic to the extreme, because the Material Universe and everybody inhabiting it are themselves chaotic to the extreme and in need of serious psychiatric therapy. However this doesn't mean there are no benevolent entities in warp, the problem is that either that specific benevolent entity is the Emperor (who's now catatonic while his soul is being used as a psychic navigation lighthouse in the Warp called the Astronomicon), or they interfere with Materium once in a billion years, and when they do, they actually do nothing of significance. Also, benevolent entities would get consumed by evil entities, and/or are quickly exaggerated or "Warp"ed into something evil due to the massive amount of suffering in the material world. The whole thing about Chaos acting to be Chaos, is... it's not exactly sentient. They just do it because of the momentum. They're not inherently... evil. Khorne is also god of courage, mercy, determination, regret, fear and honour. Nurgle is acceptance, love (yes, love), empathy, tradition and memory. Slannesh is kindness, sensuality, DRUGS, expression, individuality, HEAVY METAL, joy and admiration. Tzzentch is the god of trust, aspiration, progress, knowledge, will, change and protection. There is still, of course, the deamons, Enslavers and whatever that just eats souls, but that is simply the fault of Old Ones and Necron war (this was the whole reason the Warp got unstable, thus the reason of future creation of Chaos Gods and basically everything else bad - and people are saying that they're suprised War in Heaven didin't cause Chaos Gods to pop up - IT DID CAUSE EVERYTHING) which wouldn't dissapear the second 40K went noblebright, but the now nice guy Chaos Gods would certainly stop them from fucking up souls (they aren't exactly happy of that nowadays too, no souls - no emotions) so badly and the whole corruption you mentioned would cease, because that is simply the condensed madness of all other madnesess of Universe thrown at someone.
Honestly speaking, one of best analogies is internet. If everyone were as bad as /b/, /d/, /mlp/, etc. the whole thing would be a hellhole that would be spilling (it already does, sometimes) to "real world" too, but if used properly and the madness is kept in check it allows for much faster communication and whatnot. It's not bad per se, it's just uncontrolable.
(This proably feels like it got cut in middle because that is basically true, I have some things to do and I don't feel like scrapping the whole thing and rewriting later, so there you go).