Movement is always going to be a problem. Mobility and awareness are your biggest problems as a boxer.

Making life easy for yourself:

- Spread out macros
You may need 2 or 3 different ones and you may have to position each character manually before the fight in some cases.

- Single character movement
I use a single box with 2 monitors and I just move the mouse to the character window that needs to move and hold down the left mouse button which is bound to forward movement by default. You will need a system setup in such a way that you can continue spamming your DPS/heal keys even if your mouse is in one of your slave windows.

Single character repositioning has always been the most difficult aspect for me as you need to be aware that the character has to move, get the mouse into the correct window and then move the character and you need to do all this before the shit hits the fan and maintain your DPS/tanking/healing.

- Move all ranged characters
Usually strafing left or right to get out of AoE. I have the cursor keys bound to forwards, backwards and strafe left and right and this is passed to all my characters. With a tank I would normally unbind some of them to allow me to move the ranged group separately from the tank.

I am not instancing in WotLK yet so can't help you with strategies on specific fights but from my BC experience a lot of bosses required you to really practice group movement, single character movement and awareness to realize that the group needs to move. Especially when you are busy tanking and healing the tank while keeping DPS up at the same time.