What did you decide about the footprint? I'm wondering if they could redo just the shelf, not the whole pool, and put the seam between old and new right at the edge of the shelf. I can't say if that would be more or less noticeable than a foot print. And maybe it could leak? The problem I would have (not to rub salt in it) is that the footprint doesn't represent of bit of plaster work that was a bit "less perfect" than the rest. That I could embrace, eventually. It represents a moron who stepped in it, literally, and was completely avoidable by even the worst-skilled plasterer, let alone someone being careful. Uhg.
Or...
(I've introduced this idea to others here, with similar glitches.)
Every pool has a big ol' fat defect. Somewhere. Some worse than others. I call 'em birthmarks. That's what they are. Just like the one you have somewhere on you, it's not something you're happy about, but it's part of who you are. Well, your footprint is your pool's birthmark. Embrace it. Reduce it by making fun of it. Live with it. Love it. As you would a child no matter what his birthmark!
Mine is a big fat acid stain in my shallow end. No one but me knows it's there, but I see it all the time. Worse part, I did it myself while I was learning to care for my pool! Oh well, that's my birthmark, totally avoidable, but I did it, so I own it. It doesn't make swimming in my pool the teeny-tiniest bit less enjoyable, and that's the bottom line!!