Some how, I have to disagree with you Avenger. Judging by reading the way he put out the idea it seems he knows full well that balance isn't even an issue. Explain the "Balance" of this then if you believe it doesn't have it? I believe also, that it's the same aspect of Grab, Drag, Throw. But with less movement or a stationary grab + Hold.
Plus, Three seconds is plenty of time to get a partner to grab somebody, and A: Player B Charges beam while player A is obviously getting that hold on the person with player B ready, of course you are going to think "Hmm, well A Grabbed C, and B fired at C. But wouldn't A get hit as well?" Well of course! But since the blast radius was blocked positionally infront of A, A would take minimum to medium damage while C takes full to critical damage due to opened wide and no blocks.
Of course there would be a system to prevent grabs Obviously, maybe a quick time event *I doubt that would be interesting* so I'd say the powerlevels between the two Grabber and grabby would differ the time between actions / Grabs. There is plenty to discuss about a Grab+Hold action since it's worked well in plenty of fighter games. But he's talking purely a Team-Based skill which I find to be more enjoyable. Also the Grabber could be shocked if the Grabby breaks free for probably a second or less, .5 maybe? I personally dislike a game that allows you to grab a enemy and beat it into the ground or whatnot, I find it cheap and boring. But in a Multiplayer game like this, I find it well deserving of a real idea and not be called "stupid" just because you can't fathom anything relevant or take in anything that is not spitted from your mouth.
Just saying... lol
Good Idea, needs a touch up on the planning and information with a little more thought on "How it works" and the "How to beat it".