The more i think about this and see responses, i the more i'm weighing towards not supporting this proposal. i see merit in the idea, and would have likely supported something like this as a single market roll out for Bitshares in the beginning, but at this point i think our community has suffered from too many pivots; i also love our trading system and enjoy having a variety of markets to trade. it doesn't sit well with me trying to force volume from smartcoins people are voicing their preferences to trade (by actually trading them). it's possible some, or more, of that volume will simply disappear with discontent and more uncertainty from a major pivot.
there are always multiple solutions to the same problem, and in this context we have several other proposals to boost liquidity. One involves a complicated subsidization scheme, which is also a reasonable idea, but i prefer simply providing discounts for trading frequency.
we already have a great system, i think we're lacking on getting the word out to candidate traders. a persistent marketing campaign to retail and crypto traders is where i think we'd get the biggest bang for the effort.