I would support the idea if it's strictly limited to outputs where the public key is already published in the "receiving" transaction, i.e. P2PK. I think that's also the idea behind it. P2PKH and friends has a much easier solution, just don't reuse
It sounds like one of idea that sound interesting or cool in theory, but probably not practical enough. If someone bother to create TX that serve as collateralized legacy output, why don't they just just split their Bitcoin to many fresh/unused address as workaround?
As far as I understand the proposal, the idea is to change the game theory for quantum attacks. This means, owners of P2PK and other "vulnerable" output types should deliberately resign to move their coins only to create these landmines and making quantum attacks riskier. I.e. "for themselves" it's of course easier to move their coins to fresh addresses, but they would set up these traps as a service "for the community".
I think that idea could work, because for the P2PK owners it is an interesting "game" to try, i.e. to speculate on an attacker trying to "take it" with a quantum computer. Anybody who owns an old P2PK output from the 2009/10 era could thus be speculating on additional income.
The only problem behind the proposal is that most coins of these types are believed to be lost (or difficult to recover), with Satoshi's coins being the most prominent ones. This means: Attacking the Patoshi coins will continue to be low-risk probably (if Satoshi isn't already creating these proofs secretly ...). In general, I think there will be very few old P2PK outputs where someone even is able and willing to set up such a landmine. And that probably reduces that risk to attack them to less than 1% or so.
