In my group we play that if you forfeit using an action card you can perform a second maneuvre for free. This has actually come up a number of times and I feel makes the game more fluid.

We used it at 1st, but it is a bad idea. You undervalue range combat as well as action/support that you would use.

This weakens a lot archer / mage / non-combat Career, and makes Combat Career much better and brings a one sided combat supremacy : melee owns it all.

I also limited the number of Fatigue that can be spent/taken for mouvement manoeuvers (2 Fatigues)

It's actually an optional rule in the GM Toolkit.

You could also allow it as a stunt. Then require an easy athletics check to make it, with misfortune added for hard terrain and so on. If you do this the universal boon effect should probably be ignored for that roll, otherwise you risk players getting even more manoeuvres to spend.