A 'cut down' AM4 is probably not viable due to the need for external stabilisation from those big outboard plastic chunks. Unlike Intel's LGA sockets which have a big metal chip-guard, the PGA sockets AMD are using have nothing to protect a chip from uneven mounting pressure, and from overpressure. The worry is not so much damage to the die itself now IHS are pretty much standard, but damage to the PGA mechanism itself (which to function needs to be free-floating in order to slide), and to the clamped pins.
Removing the stabilisers entirely and providing a custom cooler (or sticking LGA-spaced holes and standoffs to correct for height difference) would run into the issue of hoping customers actually follow the exacting installation instructions to prevent damage and a swathe of RMAs. And from the continued cries of complaint over Intel's push-pin mounting (possibly one of the simplest mounting methods possible) breaking, that's not really going to go so well.