Fish will find even the least differentiation and use it as a trail. We design channels, cuts, and humps in each lake we design for our clients. I personally believe we need to design a diverse under water community in order to give all sizes of all species of fish the best advantage to grow to maturity. Channels are part of that, as long as you don't breach the bottom and cause a leak. As long as the soils have some clay content, I wouldn't expect your channels to collapse. Design them from point to point, to connect your other prominent features.

Teach a man to grow fish...
He can teach to catch fish...