If you are using default drivers for the Optical Drive, you might be able to find specific drivers from the manufacturer that behave better. Or vice versa.
Generally, this issue is a combination of the way MC tries to take control of the drive (low-level control, which provides better CD rips), the hardware in the computer and its drivers (USB port), the operating system, the hardware in the Optical Drive, and the driver used for the Optical Drive.
It can be pretty hard to work out which bit is the problem, and even then, it may not be possible to fix.
I did look at your crash report the other day. I had forgotten that. I can't work out what the cause is from that anyway, but the;
Exception Type: EXC_BAD_ACCESS (SIGSEGV)
Exception Codes: KERN_INVALID_ADDRESS at 0x00007fa2b5141a2c
Exception Note: EXC_CORPSE_NOTIFY
doesn't look good. Probably points to the USB driver in combination with the way MC accesses the drive.
I assume that when the Optical Drive was mounted internally it was on a SATA connection? If you were on Windows, I recommend exposing a SATA (i.e. eSATA) connection and putting the drive in a SATA capable external enclosure. But I guess that isn't going to happen on a Mac?