And the problem with that is what ?
You are afraid that you might like it. You migrate and they will kill the project ?
If yes then...well...same can happen to any kind of software / project
If yes then...well...same can happen to any kind of software / project
I'm not worried though. This is a neat hack, and may be useful for some people who for whatever personal reason won't switch to Linux proper, but it will not gain anything like the dominance required to push through incompatibilities. Unix applications already deal with a heterogenous environment, to say the least, and Winux will just be one more participant; not a particularly important one at that.
Everyone migrates, draining valuable developer resources from projects like cygwin, mingw and colinux and others. When Microsoft kills it, they will have killed off not only their project, but also the community projects that could replace it.
Meanwhile, because the NT kernel has vastly different performance characteristics (e.g., bad forking performance), we're going to see an increase of "Linux/NT" optimized software that will perform poorly on native Linux kernels, pressuring more developers (and ops) to buy into Microsoft's effectively proprietary solution, completing a vendor lock-in that will continue to bleed the industry long after it stopped being beneficial (see also, every other instance of vendor lock-in ever).