I think while auto-fill is active, there should be very little punishment for dodging. If you get a role you absolutely can't play and no one will trade, you should dodge. I encourage dodging, because chances are high we will lose and you will be a large reason why. Would you rather lose 3 LP or 15+ LP? If I get auto-filled to ADC and no one will switch, I dodge because I don't want to hold my team back and I'd rather take the 3 LP punishment than the 15 Lp for a loss. This is Ranked though.
In Normals there is absolutely no to dodge, if you get auto-filled to a role you can't play this is a good time to practice. In these instances, there should be a bigger punishment for dodging.