"Gladiator" look is a reference to the Ridley Scott film Gladiator. The actions scenes have a staccato movement associated with really high shutter speeds over 1/1000 sec. Since most films are shot 24P at 1/50 sec, you get a more pleasing motion blur. But if you want to do slow motion, then you need to shoot at 1/100 or faster shutter speed. It's all in the look that you want to achieve. Slower shutter speed means more motion blur, faster shutter speed means less blur and more stuttering movement. Again play around with different settings to get the look you want.
As for the A function, well it really is a stills camera first. So the legacy functions of A, S, M, and P are all there. You can also change the movie mode to shoot in S function. Go to movie mode on the dial, enter the menus, go to the camcorder icon menu, exposure mode and set to S. Now all you see is the shutter speed, the aperture value is gone. If you have ISO and WB both on Auto, then those icons disappear as well. So now all you do is set your shutter speed and everything else is on auto. In dark scenes it will automatically go for the widest aperture, then set the ISO for you.