I went through all the replies, and there is a consensus on the first two proposals (disabling sICX borrow and removing OMM rewards).
I think these two should be implemented immediately. On the other hand, subtracting total sICX borrows from the sICX supplies to calculate the net ICX ownership seems to be a fair approach.
It was noted that there might be a situation where some might borrow sICX by depositing stable coins. In that case, those people will carry a negative sICX net balance.
If we try to calculate the total sum of those with negative sICX net balance, we will end up with some kind of surplus. Because of this surplus, it may not be possible to get 1 ICE for every underlying ICX staked as sICX.
However, that surplus is not expected to be very high compared to the total circulating sICX. With that assumption, we may receive a little less than 1 ICE per ICX, which is okay for me, but I am not sure what others think.