A lot of high level ingenuity and engineering has gone into the development of the original Mirage Drive, as well as the Turbos. I would be very hesitant about making any permanent modifications to a drive simply for skinny water. I mean, you can't simply glue the pieces back together when you need to use the regular drive. And, I think carrying two drives, or two sets of flippers and masts around with you will get old very quickly unless you have a lot more time, patience, storage, or hatch accessibility than a lot of us have.
As Matt Miller points out, the partial extension or flutter kick works very well in skinny water. Any shallower than that, then I go to my paddle, or especially to my Law or poling stick. As Roadrunner mentioned, having a short (5 foot) poling stick has been of more utility than I ever imagined when I first designed mine. I rarely even use my paddle anymore since the poling stick makes a surprisingly good J-stroke paddle (with the terminal 4-way fitting), in addition to keeping me out of trouble around docks, floats, piers, anchored boats, oyster reefs, rocks, etc., where I use it to push off. In addition, it is perfect for launching and returning around here (no surf!), both as a J-stroke paddle, and as a poling stick. It is a lot quicker to get it out of my portside bungee and into use than my paddle, because of its much shorter length. It also avoids developing that "ragged edge" effect on a paddle blade that has been used for pushing off various hard (and often rough-surfaced) objects, especially like oyster reefs around here. The tips of my Mirage drive flippers will issue a hearty "amen" to that after I unexpectedly get carried in seconds right up onto a submerged (and unseen) oyster reef from deeper water by a strong-running tidal current! No time to even think about shifting to a drive with shorter flippers, besides which there is no way to swap out drives once you are aground anyway! BTW, that is a formula for a dump when your Mirage Drive flippers get stuck on a rock or oyster reef or even in soft mud and there is a strong current running. Being able to get my poling stick out, around my rods and rodholders, and into action in just a few seconds has kept me out of serious trouble on more than one occasion.
In addition, a lot of folks down here don't even fool with an anchor on the flats, but use a stake-out pole stuck in the bottom sediment to secure their yak when they get out to wade-fish, or â€œanchorâ€