I agree getting 10g wire on a deans plug is tough . But i found it's even thougher getting 10g wire on a traxxas plug .The chinese plugs at half the cost or less would be hard to pass up .
To solder 8GA to Deans, I tin the end of the wire and then use a Dremel tool to make a flat spot on the tinned end. Makes the joint a little smaller, and provides better contact will less solder. Yeah, it removes some wire, but the Deans plug metal has less cross-sectional area than the wire anyway, not to mention the reduced amount is made up for by the fact that solder is filling in all the little voids between wires. This might be possible to do it to Trx plugs too, as long as the wire fits into the housing.
I don't like the look of TRX plugs...Im not too sure why but I just don't like them. I was looking at some plugs and i'm putting an order together now but they seem to be out of stock(the yellow dean looking ones)...