Many Gemini lots did not sell. 148 of the first 443 ancients are on the unsold list: http://www.geminiauction.com/unsold.asp?utm_source=Copy of Copy of Copy of CCE & Gemini&utm_campaign=Gemini XIII Web Site Launch&utm_medium=email I don't think the bidding was weak, rather, it was high estimates.
I tend to agree with your observation. Looking through the unsolds, they're almost uniformly excellent coins, but the opening bids just seem relatively high. I speculate that had the opening bids been lower, many of the unsolds would have actually reached at least their minimums, and possibly even more.
Never mind the estimates, the opening bids are too high, once you factor in the buyer's fees and shipping.
The fees definitely made me think twice-- 24%, for some folks (19%, + 3% if paying by credit card, + 2% if bidding live online). I prebid on only one lot (lost it) and did bid live on a few. You can pay by check if the account is in the US, so for some of us at least we can skip that extra credit card fee.