zahavasdad, that is an interesting and telling comparison.
We can conclude from your comparison that punishment does not indicate severity of sin since murder is such a serious sin, it is one of the three aveiros that one should let themselves be killed for rather than commit, but it is not a chiav to give up one’s life when being forced to rip toilet paper on Shabbos. In fact, one would be foolish to give up one’s life if forced to rip toilet paper on Shabbos. So if punishment would be accordingly to the severity of the sin, murder would have to have a much greater punishment, or rather tearing on Shabbos should not have such a severe punishment if punishment we’re meted out according to the severity of the sin.
Since we have a tendency to percieve some things as being small and irrelevant sins, I believe that severe punishment teaches us that these sins are not small and are not to be taken lightly. But it is still not an indicator how big or small a sin is.