Some places are tough to land fish for sure. Esp. summer runs that just never give up on light tackle- good recipe for losing fish at the bank. Hey, at least you're hooking fish!
In the situation you described, I see 2 possibilities (assuming you can't go up or downstream to a better landing spot):
1. Net: If you have a partner, try to net it before you bring it in to the really shallow water. Tougher to do on your own, but still maybe possible.
2. Tail: Tire the fish out well and lead it in toward the shallower water. Rather than backing up the bank with the fish behind in the water, get out far enough so you can lead the fish in front of you.
At the point where the fish scrapes rocks 2 things will happen- if he really doesn't like it and still has the spunk he'll probably take off- or he will accept the shallowness because he is done and lay there somewhat calmly for a few seconds at least. Maintain tension from the rod on the fishes head, come from behind and grasp the section right above the tail. Easier with a glove or rag for a better grip. Also easier with a heavier leader and a shorter rod. Being behind the fish gives you a chance if he starts kicking again or the leader breaks or whatever. You can still scoop the fish toward the bank and I have seen boots put a few on the bank in that scenario.
Regarding the gaff idea, I'm pretty sure a rounded hook similar to a gaff would definitely be considered a gaff.
If you're close enough to gaff it, the tailing should work (it does take practice).
This vid shows the basic idea, but the execution leaves something to be desired. I would not grab the rod like he does. Looks like a longer rod, which makes timing more important.
https://www.youtube.com/watch?v=1hvpZbpDhWcTips here better than I can type it
https://www.deneki.com/2015/01/landing-fish-without-a-net/
