Currently, we have floods of garbage hitting Steam, with no curation at all. Pre-Greenlight, Steam was a closed shop that was hard to get into.
What is needed is a healthy balance, that doesn't have zero chances for an indie game to be seen because it's buried under all the AAA titles, yet doesn't allow trash like Slaughtering Grounds to be sold.
The article suggests getting Valve employees to playtest any submission - however, I feel this still wouldn't work due to Valve's 2 main issues. Their flat structure, where people work on what they want - who wants to look after content curation? Secondly, they take a cut of every game sold - regardless of how awful it is. They are financially incentivised to keep subpar (or even scammy) games on the store.
I'm not going to pretend I have a solution, but I feel all the issues with the Steam store currently are issues of Valve's own making - the problem is, they don't (seem to, at the very least) care.