Each time I use the MagicShine, I have to connect and then disconnect the wires. To me, it seems like a "mean time before failure" type situation. Shouldn't there be a switch like thing? Also when I'm riding in daylight, that open connector seems to be subject to any airborne particles that might lodge inside. What's the solution?

I just take the lighthead off the bike when not in use; put it in a bag or pocket. A rubber cap of some sort would also keep the connector clean. Of course, you could also buy a Y-cable from Geomangear or whomever and use that for charging without dismounting the assembly. Then you could keep the primary connection permanent; even put a heatshrink boot on it.

The other issue is waterproofing the battery assembly. There is a thread about this on BROL, if you search there.

The same is true with virtually all external battery pack bike headlights. If they use well made connectors there should not be a problem with connecting/disconnecting for thousands of cycles. I have not seen anything yet indicating this is a problem.

Airborne particles are not going to be the death of the connector. It'll die of the strain of being connected and disconnected first.