Yea if you are using the escort order then they're not going to do much aside from covering your rear. From what I understand though (and what I've observed anecdotally), the smaller frigates do have behavior where they will move in-front of you to shield tank some damage when they are on escort duty. Its actually behavior that is noticeable with a lot of enemy AI. If you ever see like a group of enemy ships moving together, the escorting frigates will move forward to absorb your hits if you've fluxed out the main cruiser they were escorting. Key distinction between frigates and destroyers and cruisers on escort duty is that a lot of the larger destroyer and higher ships just don't move or accelerate fast enough to get in front of you in-time to help you soak hits.
Escort command is the absolute worst. For example, when I was young and naive I used to send Drovers to escort Conquests (so the fighters could cover it from bombers and other fighters flanking from the sides). What happened most of the time to those Drovers is that while Conquest is duking it out with some other capital - and runs out of flux - a Drover would jump in between them and tank the enemy capital's hits with its shield. Yea, it ends about as well as you suspect.
Another problem is that all escorting ships are trying to do the same thing and stay away from the ship they are escorting at the same range. Once you have about 3-4 escorts this leads to them colliding, pushing each other, blocking etc.
I think its not even the problem of AI but of command interface. There is no way to differentiate between "cover this ship" (taking flank and tanking some hits) and "follow and take cover behind this ship" (staying away from the frontline and taking shots at enemies with fighters, rockets, long range beams and ballistics). There is also a problem of orders being per target, not per ship. E.g. you can't have one ship being targeted by fighters and being eliminated simultaneously, the carrier and battleship you designate to kill that one conquest will either both stay away and take potshots (if you select "E" engage or fighter wing strikes on the ship) or will both close in (if you select "C" eliminate).
With the current AI I find it best to just let ships do just stay on search& destroy 95% of the time and 5% of the time I use waypoints to corral where I want them. Not escorts, not eliminate, just waypoints.