I'm not posting this in the bugs thread, since as far as I can tell from the rules post this is working as intended, but Fire at Will allows you to more or less completely negate jump shock for a well-trained fleet. If you press the Fire at Will button after jumping it seems to overwrite the fire delay from jump shock, and if your fleet is trained then you'll end up with little to no delay. Of course you don't get to choose your targets, and in some cases that's a big downside, but it's usually better than the alternative of not firing at all, and if your fleet outnumbers the enemy then it's often not a huge problem.
This makes taking a jump point generally much easier, but it's especially unbalanced because the AI has a tendency to jump through the jump points when attacked. So you jump through a JP into an enemy fleet, the enemy jumps to escape you, you jump back and chase them -- and now you can use Fire at Will to wipe them out while they recover from the jump shock.
Was Fire at Will intended to negate jump shock, or just reduce the normal fire delays when crews are untrained? The balance issues could be fixed by making the AI use Fire at Will as well to counter the advantage the player has, but that just makes jump shock kind of pointless. I think it would make the most sense to change Fire at Will so that it doesn't affect jump shock.