I use 4 conductor + shield all the time with my stereo mics without a problem. My standard mic cable has a 5-pin XLR on each end. As you say, it cuts down on the number of cables and weight you need to pack, and speeds up setup/teardown time. I made 3-pin to 5-pin XLR Y adapters; that way I can hook together as many 5-pin cable I need and terminate it with a Y to get back to the 3-pin world.
Many stereo mics has 5-pin connectors, but the pinout is not standard so I sometimes need to use a 5-pin to 5-pin adapter to get the correct pins connected together.
I have never had a problem with crosstalk or noise with my system. Most stereo mic manufacturers supply their mics with a single cable that carries both L & R channels without a separate L & R shield. It ain’t the shield, it’s the CMR that makes it all work.