It is obviously a great promo! But it would be nice to have something similar for smaller ranks, obviously not as much money. For instance you could have a bronze, silver and even gold challange, obviously people can progress through ranks as the month goes on so your entered into the competition for the rank you started the month on. As for prizes, well thats up to you guys, but I think some sort of freeroll for top100(?) would be a great idea.
Thanks
Hello irregularity,
For players who are starting out at PokerStrategy our main offering is the content. Videos, coachings, articles, professional hand evaluations all take a lot of resources and are worth their weight in gold when it comes to moving up the limits. As such they are the direct 'benefit' that any bronze-platinum members have. Once a player has reached a high level thanks to the provided content the top250 promo is the "added bonus" on top of this already encompassing offer.
This is why we don't have similar things for smaller ranks (aside from this being next to impossible to put into practice - since as you said people rise in rank. As such it would always be the players who went from bronze/silver/gold to diamond that would win - meaning it would also be a diamond promo)
Instead we simply have other offers such as the current Mansion Series freerolls : http://www.pokerstrategy.com/news/pokerstrategy/PokerStrategy.com-Mansion-Poker-Series-Enters-A-New-Round_15207 as well as the generally best bonus offers around 
Best regards
SoyCD
