Implementing KGW or changing the retarget interval will require code to be changed, and everybody to download new clients. Plus the stigma of a "hard fork".
A matching bounty on each block mined, up until the difficulty reset, would require just a bit of accounting work. (And ~3500 PTS.) The bounties could even be paid out over time, say every 100 blocks or something. Pools would have to make some changes, but they would just have to keep track of amounts credited to miners, and double them when they receive the bounty payment.
Of course, that doesn't solve the problem long-term; the next DAC snapshot announcement will undoubtedly bring in a lot of new mining power, and after the snapshot, price will drop and the miners will go away again, and the loyal miners will be stuck with the high difficulty again.