I don't rely on preset formation at all.

I use "banding" (holding down ctrl and draw a box) to tell my units exactly where they should stand. A lot of micro management and click-clickity-clicks, but I don't need to remember which preset formation am having.

The down side of that is my formation is not as pretty as someone may like. I received many comments from allies telling me to learn managing my troops better, put them in nice formation, nice order, etc. Appreciate those comments, but it is hard for me to relearn the tricks.

In RTW, formations could be "wheeled" and that's a nice feature MTW lack.