Exactly what PiT said.
Also, there is something to committing to a strategy and letting it play out. It seems that every few months we see a lower chamber proposed to replace the regions, but that argument gets weaker as efforts to strengthen regional activity through other means are implemented. Changing horses midrace seems less and less appealing.
The case could have been made a year or two ago that regions were a meaningless piece of the game. That really isn't the case today. Let's see where the revitalized regions take us before we throw them under the bus.
The case I'm making is that we aren't losing anything by disposing of the regions. This isn't a case of switching horses but rather feeding it a different type of nutrient-rich water for the stretch run after we observed that it was tiring.
Your idea might work, but we have no idea whether it will be the greatest boon to the game or whether it will kill the game. On the other hand, regions have proven to be a steady and reliable means of introducing new players to the game. Are they perfect? Surely not. Is there a better alternative? There always is. But I feel the risks involved in most of the proposed ideas is such that it far outweighs the benefits of switching.
Reform is only truly needed when something is broken or an alternative is clearly better. Until you prove that the regions are truly broken (which cannot be argued right now) or that your idea is proven to be beneficial (which is only possible by testing it in a region or two, partially boosting the opposing view), I can't get behind it.