Someone didn't get the memo, apparently, but they posted an interesting idea to help balance RTL a little towards the OL side in Silver and Gold. Posted here below verbatim.
Usagi Said:
I'm fairly new to this game, but here is an idea I came up with to help keep balance in an otherwise lopsided RTL game.
Looking through the general flow of the game, there is a function (EG the legendary locations) to help the heros, should they be behind in conquest. However, theres no similer function for the overlord player. So, the mechanic I came up with is very simple. At the point of a campaign level up (copper to silver, etc.) if the overlord is behind in conquest tokens, for the rest of the campaign all monsters get +1 armor and +10% wounds (minimum 1, rounded up at .5). So a monster with 3 armor and 10 hp, would have 4 armor and 11 hp for the rest of the game after that.
THis also works as a balancer for 5 heros, I have found, to just let the overlord start with +1 armor and +10%hp at copper level.
We haven't used this much, but it sems to work. I'd like to hear other peoples opinions or projections on how this could play out overall, though.