To be honest, the VPN fickleness is not just Windows' fault. That falls largely on the VPN vendors. If you think one is a problem, see what happens if you need access to networks behind different vendor's VPNs... (I'm not talking about needing simultaneous access, just trying to keep the things from killing each other and Windows.)
Most VPNs I've encountered are configured to cut the client off all networks except the work net. That is normally a gateway policy and the client has no control over it. Usually to prevent exactly what Static is doing ;-)
I haven't used Cisco's yet, but it is possible that flipping the LAN access checkbox causes the gateway to lock the client out at that time.
For the share access issue: there is a big fork in the road. Prior to OSX Lion. Apple used Samba. With Lion, they switched to a proprietary reimplementation of SMB. Behavior and possible fixes depend on exactly what is on the Mac Mini.