When you think about it, two users searching for a game - one using automatch and the other one creating a custom game - almost want the same thing: They both want to play a game with specific settings. (And of course both want to find such a game as quickly as possible.)
The only difference between the two is that one player is more specific in the settings of the game than the other. And in case of the custom game the player is not necessarily more specific because he wants to but instead because he has to be more specific! The UI just doesn’t give him the possibility to create a more open game request.
The player creating the custom game might be very open to all kind of settings but currently he just can’t express that properly.
Actually, if creating a custom game would enable you to specify settings as “no preference”, “prefer” and “require”, you could already express the same kind of search as you can with the automatch option.
So consolidating the custom game options and the automatch options into one common place where you can specify your game settings and then throwing all the submitted game searches of all the players into one pool and match them against each other would be ideal it seems. Allowing a user to store some presets for game searches - like what is currently available via the automatch options “Blitz”, “Normal” and “Correspondence” - would certainly continue to make sense.
This would free the user from closely watching a constantly changing (and moving) list of custom game requests, understanding what all these time settings mean (“4m+ 30s up to 5m”, “15m+5x30s”, “+ 1d/2”, “+2x12s”, … (actually to this day for some of them I have no clue what they mean!)) and try to hit the right (and very small!) “Accept” button in time. Overall an experience that can be really painful for example if you are a beginner to the game and/or to the server or if you are in your 70s for example and consuming all that information and clicking a small button might take you a bit longer than a few seconds already.