The difference between sponsors and this issue is more subtle. The issue Suhas raised was with a variant of sponsors trying to address a second criticism, not sponsors itself, which is secure against this.
I think I can make this clear by defining a few different properties:
Strong Reorgability: The transaction graph can be arbitrarily reorged into any series of blocks as long as dependency order/timelocks are respected.
Simple Existential Reorgability: The transaction graph can be reorged into a different series of blocks, and it is not computationally difficult to find such an ordering.
Epsilon-Strong Reorgability: The transaction graph can be arbitrarily reorged into any series of blocks as long as dependency order/timelocks are respected, up to Epsilon blocks.
Epsilon: Simple Existential Reorgability: The transaction graph can be reorged into a different series of blocks, and it is not computationally difficult to find such an ordering, up to epsilon blocks.
Perfect Reorgability: The transaction graph can be reorged into a different series of blocks, but the transactions themselves are already locked in.
Perfect Reorgability doesn't exist in Bitcoin because unconfirmed transactions can be double spent which invalidates descendants. Notably, for a subset of the graph which is CTV Congestion control tree expansions, perfect reorg ability would exist, so it's not just a bullshit concept to think about :)
The sponsors proposal is a change from Epsilon-Strong Reorgability to Epsilon-Weak Reorgability. It's not clear to me that there is any functional reason to rely on Strongness when Bitcoin's reorgability is already not Perfect, so a reorg generator with malicious intent can already disturb the tx graph. Epsion-Weak Reorgability seems to be a sufficient property.
Do you disagree with that?
Best,
Jeremy