I spent several hours testing different options. From PlayOnMac to the latest version 4.7 of raw wine installation. None of them seemed to make much difference on the startup/exit times. And, are increasingly complex solutions that will probably not help many people due to the difficulty to set up.
The biggest factor seemed to be once I put in my FG license and had all my extensions and modules in their respective directories, that's when things got slow. For people using the free client to play on someone else's game, I don't think the solution from FG is bad at all.
So, I am just going to use bootcamp until Unity is released. Luckily at the current time you can use bootcamp and use an unlicensed windows 10 install that just has registration nagging all over, but none of it seems to be interfering with fantasy grounds. This seems fine for the coming few months I need it, and will be easily removed once Unity is released.