The DC penalty system is good as it is now, though it should be made harsher once the issues are addressed. A percentage based system was in effect for years, and we all know how that went....COMPLETE FAILURE! Some streamers were DCing left and right, with no penalty at all due the number of hours that they play.
Now we have a system in place that is effective, everyone is FINALLY agreeing that DCs are just a symptom of much greater issues. The DC system should not be neutered because of the greater issues. The greater issues need to be addressed individually. Reducing the DC penalty will significantly hurt the game, and will just hide the greater issues.
This is a case where you need to seriously break it, in order to find the weaknesses.
Good cya kid!