The penalty is fine. No need to change, its so players dont abandon for any reason and ruin it for others. I will list counters to every issue a player may have right now.
1: Issue: Dinner is Ready. Gotta go now. "No, if you knew dinner was coming up soon you should not have accepted going into UQ"
2: My cat is on fire. "You mean you want to leave because you feel you wont get an easy carry? Next"
3: My connection was spotty all night "Well then if it is, dont just go back into the UQ, its sucks but just wait till your connection is better"
4: Im sick "Then why are you up playing?"
5: My Game client crashed, again. "Stop modding your client then"
6: Im not using mods... "Stop watching pronz then"
7: I dont watch Pronz.... "Then Reinstall the game or reset your O.S, your PC is sick"
8: I gotta go to bed "Seriously? Refer to the first example"
I can go on and on, but you get it now.
Penalties need to stay strict like this. Otherwise we will get a buncha players, mostly the casual type, whos looking for a carry or a fast clear, not gonna get either, they then leave, and go in again for another party hoping to get lucky next time. It sucks. But it mostly works.