Perhaps what is needed is a rule change much further back in the process. The poor fellow who was bumped and bruised had paid for, and was allocated a seat. Short of his being in violation of a cabin safety regulation, he was entitled to ride in the seat for which he had paid. The airline has no right to presume that they can repurpose that seat, or otherwise overbook the flight.
If a passenger, who has paid for a seat fails to board, the seat should fly empty, and the non flier charged full price for it. The airline has no right to overbook on the chance that they might sell some seats twice! Overbooking should be outlawed. If, in the moments before gate close, the paying passenger has not shown up, them perhaps the airline can double dip, and sell to the seat to standby passenger, who had not confirmed seat anyway.
I agree, an $800 travel voucher would not get my attention at all, my day is worth much more to me than that. And that travel voucher.... puts you into a low cost seat next time, from which you can be bumped!
My money is good, the seat it bought should be too!
If I were AA, my next ad campaign would feature the following: "At American, if we overbook we'll fatten your wallet, NOT your lip."