After much consideration I have decided on a knife.
I had the steel version of that same knife. I would stay away from TI knives for an oh **** knife. Ti is great for not rusting, doesn't hold an edge or cut all that well in a hurry.
The blades are short and the serations are wrong. It is almost the fixed blade version of a multi-tool(doing several things at once, none as well as a dedicated blade).
If it's only for the use you've outlined I would go with a good modern steel(some of the newer new powdered steels come to mind) with a longer scallopped serration and thin blade. Blunted round tip, fixed blade, single type . For dive knives those are fine, the hook is a benefit, I used mine to find and trap fishing line I couldn't see to cut(tangled up on my regulator behind my head. Thick is great for prying. In a large rope tangled situation where time mattered I would never trust it. The sharp portion is too short, the handle is too skinny. The sheath doesn't retain well enough on it's own, and hangs on too well when you want the knife. Fine if you can just swim down and dig it out of the mud and go back to whatever you are messing about with. Not fine if you're trying to cut yourself free in a hurry.
I would stick exclusively to river rescue type knives, or sailing knives.
EDIT: For example the Emerson La Griffe, good retention, small profile, finger hole helps to index it. There is always the debate of whether you should have a knife tethered or not, propenents say yes because losing it when tangled isn't going to help, those against it say it's one more thing to tangle and if you can't reach the problem you're up the creek, or worse if it falls out of the sheath and you get bitten by it while you're flailing around.
CRKT etc curved river knives are a cheaper version, but IMO the Emerson knives are better. Ernie Emerson is a really solid guy, though I would hate to lose one of his customs over the side, the prices on his production ones aren't bad.