Just a random idea that may very well take some work and be otherwise impractical.
But building on the "handing out some free XP" notion, perhaps give every character (or every character currently identified as active) a free 100k (or some number)experience payout. That could benefit all the characters in the game, from the ones who have trudged up the ranks the hard way to the ones who are languishing in the lower levels with no opponents, or very few.
That way it would be an across the board benefit for all characters. Those characters/players on the higher end obviously wouldn't need it or benefit from it as much,nor should they, but it would at least be something, and for the lower level characters they could do quite a bit with 100k (or some number) and could more rapidly bump their characters up into the more competitive and active tiers.
Maybe make it a yearly thing, like a Christmas bonus for those few players who actually stick around and keep playing. It might be tedious to give a boost to every single character or active character, but it's not like the mods of this section have anything else to do right now