Stable difficulty? Do you mean longer lasting block window, like 2016 on BTC? I do not agree, a fast changing difficulty is a must for a coin with minority hashrate.
With fast changing difficulty, miners will never move all hash to BCH, because it will never be profitable enough, unless BCH price would increase to BTCs level..
True, but it does not incentivize miners to switch to BCH long terms, as soon after they switch, difficulty rises instantly, so they are best to switch back to BTC again.