Also another very good reason against an early day end: It (often) prevents the victim having a chance to defend themselves. If they have an important role like the cop, doctor or vigilante, we do NOT want to lynch them, and if we're in the mentality of 'don't lynch until we're sure' they get more time to claim. In fact, in general I consider giving the final vote suspicious, if the general consensus of everyone isn't already that the person has no chance to defend themselves successfully, and there's no more information to gain from the day. A person being at -1 from lynch is far from implying that.
I absolutely agree with your point about allowing any and all chance for a defense. I don't, however, find the ultimate vote as scummy. It COULD be a Mafia, but is a whole lot more dangerous place for them to put themselves.
Consider, with 8 to lynch, if a player already has 7, and there is an unvoted Mafia, there is a good chance the person will be lynched regardless. There must be some consensus that got the person to 7 to begin with, right? And if any vote slot will naturally "appear" scummy, it's the final one. I believe Mafia are MUCH more inclined not to vote there, and then use the innocent person who does as a target day 2. The penultimate vote is much more revealing to me. Thoughts?