I think locking is a mistake, as it is artificial behavior and no longer organic.
The long-term results are unforeseeable vs real-time results. I think something simpler, like randomizing the time to rebase is a better solution.
This prevents rebase hoppers from being able to coordinate their withdrawal and sell-offs, without watching their screen all day.
In a scenario where a large portion of OHM is locked for a year, I would naturally start viewing that day as an impending massive sell-off...this would make me move to DAI the day before for "just in case" there is a massive price dump...if more people think the same way then they would do the same, causing a dump just before each payout.
A self-fulfilling prophecy.
This would be true of every OHM payout day. The day before could be a liquidation event.
This would result in the dumpers on the second day, selling their OHM rewards cheap to be scooped up by the DAI holders at discount.
Compared to current behaviour where you have various individuals, at random, rebase hopping you will create a larger problem of, via forcing artificial behaviour, the potential of artficial price dumps compared to organic ones.
I also think we are too early in this protocol to make such a drastic change. Lets at least give the current state 6 months of organic behavior to see how it evolves naturally.
Randomizing rebases throughout the day is a less drastic but likely effective solution, than locking imo.