This will be a boon for low-capitalized peeps, if they follow the MGC model. I see this as more good than bad. Think about it. It will allow for more liquidity as small retail gets used to trading the patterns of the minis, and give them confidence to scale up. Hell, I'll dive into it, so long as the performance bond requirements make logical sense.
Just saw that they are having the same pip sizes as the 'Minis...this will help. The currency minis/micros have a larger pip size, i.e higher spread price. That will help. But I STILL dont like that they will have two ways to essentially trade the exact same product...I wish they'd just get rid of the mini, and only do the micros so the volume is concentrated in one product. I don't want all the dumb money in the micros, where it will cost more in terms of relative fees to trade.
I would have prefered a Micro E-mini Future that is $25/point or 1/2 the emini. 1/10th is too small and commissions and fees will be too high to actively trade. Seems like the CME wants to attract those with very little and still want leverage. I'm not a fan.
I don't trade gold (didnt even know there was a mini), and didn't/don't anticipate the opportunities to last for more than a tick or two (i.e only the HFT MMs could take it advantage of it). Intuitively though, I would expect there to be a lead/lag relationship between GC & MGC. I could be wrong... Did you look at the book & ticks?