How To Fix Greenlight
1) Look at the top twenty right now, and approve them immediately. Shut down Greenlight.
2) Is it available on GOG? Approve it.
3) Is it available on consoles (excluding Xbox Indies. There's enough junk on there to put on exception for it.)? Approve it.
4) (in case of iOS port) Has Apple ever given it free advertising? If so, approve it.
5) Open Steamworks API to everyone who paid the Greenlight fee, introduce a widget whereby it can be implemented easily on a developer's site, handle payment through Steam's servers and output a Steam key/instant addition to a Steam account, while Valve carries on creaming off 20% on top (less because it's not on Steampowered.com). Rebrand the Greenlight fee as "Steamworks access fee" and start keeping the money.
6) Use the widget data to invite the most successful games onto Steam proper, while the less successful games still get the money from the "no Steam no sale" guys. Everyone's a winner.
7) Oh, and start manually accepting games again, although most will probably be satisfied with step 5.