Fair enough, but the risk could also be mitigated by relocating the author/curator/commentor rewards to interest rewards. Currently, author/curator rewards takes up about 72% of the inflation with staked interest at 16.8% and witnesses at 11.2% of the inflation pool.
By cutting the author/curator inflation in half, you could have 35% of it remaining and relocated mostly to interest. If 10% went to witnesses and 25% went to staked interest with 37% eliminated, you could keep staked voters in control while making the witness role more lucrative and thus more secure and competitive.
That would mean interest would receive 41.8% of current inflation while witnesses receive 21.2% of current inflation and a cut in total inflation of 37%. Staking for interest, SP and RC delegations could prove more lucrative for stakers, potentially resulting in an increased demand for the supply.