I have thought about this before and it seems to be a harder issue to solve than one would think. Even EGS does not solve the issue, but they have fewer titles and less dynamic movement, thanks to a lack of algorithms.Why are Valve's people saying pre-orders might hurt your sales – hypothesis
Why we are being discouraged from doing pre-orders on Steam? Is there a merrit behind it? If so - what is a reason? Some observation from the recent release of Ghostrunner and conclussion or two coming out it.www.gamedeveloper.com
There is a quirk with Steam's preorder system where if you open preorders too early, your visibility will get knocked down by the algorithm at release as preorders and post release purchases are considered two separate products and any preorders made months ago won't contribute to post release visibility. Basically Valve encourages everyone but the largest publishers to hold off on preorders to avoid this. EGS doesn't have a store algorithm so they can open preorders ASAP.
I think a few options for Valve would be a specific tab for Popular Upcoming Preorders or something that narrows the population to upcoming games folks can actually purchase in advance. There are others ways of doing some hokey math to bucket sales or apply some more obvious kicker when a game launches to make sure it appears in advance on the Popular Upcoming and then on the New & Trending when it launches, but I think it would be ill advised to make any changes to the Top Sellers, even though the issue stems to being buried on that tab. Other options, Valve could feature preorders in a few other ways, like in monthly top sellers lists looking at top preorders or bring back the Steam lab test for running an automatic show.