Better reviews and player feedback would help; Valve recently started showing user reviews on game pages, which might be useful. Previously all you had was a metacritic score (nearly useless) and the utterly meaningless 'friends who own this game' UI, which has been broken and displaying incorrect data for years.

Steam also has virtually zero discovery features, which makes it hard to find games that actually fit your interests. The new tagging feature might solve this eventually, once it stops being complete noise.