What of the approximately one trillion threads of screeching about high fees back in the day? I guess memories are short but they'll come back with a vengeance if it happens again.
Coinbase can't move back and forth just based on how congested or not congested the network is. If Coinbase batches transactions right now, people complain about slow withdrawals and demand instant withdrawals. If Coinbase isn't doing anything and just maintains its current roadmap of instant withdrawals, people will still complain later on when the fees start shooting up again. In other words, it's near impossible to satisfy people, regardless of what Coinbase ends up doing.
Considering that high fees are only high for short periods of time, I think that Coinbase's roadmap of offering instant withdrawals is the best formula to utilize.