Unlike previous FunctorKey replacements, Coord compound Keys are used in the minimal schema for SimpleTable and SourceTable, which makes removing them problematic.
Remove in-memory support of old-version afw::table objects
Measurement transforms for centroids
swinbank, this work has already been completed, by you, I think, in working on the measurement transformations. But I can't find the issue to link to in order to close it as a duplicate. Do remember where that work was done?
I added CoordKey in DM-2306. But that didn't address the second part of this issue ("to replace Coord compound keys"): you probably know better than I do whether that's a simple drop-in change, or if their use in Simple and SourceTable means there's extra complexity to handle.
The CoordKey was added in DM-2306, and Coord compound keys were removed in DM-1766.