My solution to this was to simply find people rated higher and challenge them directly. Picking a higher rated open seek also works, of course, but you have to be pretty quick about it or someone else will get the game you want.
I'm pretty much in agreement with your thinking on this, though.
I am wondering: What is the rationale behind requiring open challenges to include your own rating within the opponent's rating range (e.g., if my rating is 1550, I cannot create an open challenge for opponents in the 1650-1750 range)? Why not let the players decide if they want to "play up"?
It makes more sense to allow open challenges to have ANY rating range. If no players find the challenge acceptable, then no one will take the challenge.