Originally the role was just needing those three players dead, but with no checks. The checks with the condition of lynching a villager I thought would add interesting gameplay of actively trying to get a player lynched instead of simply coasting by and living. I do really like the role, all said and done, especially when compared to a survivor or a regular lyncher.
I think the win condition was hard and could have been slightly buffed (maybe if neutral let it know there is no village alignment checker to give it a false claim in addition to knowing alignment of its checks? maybe instant knowledge of the last villager needed to be lynched if one dies at night? maybe give it an every night check?), but I think the role was hurt by trying to play it as town-sided in the early game. I think the playstyle needed to be the opposite of how it was taken: you need to appear scummy enough not to be night killed and can weasel your way out of being lynched by being townie as need be. I think the role wasn't unwinnable and was overall fair, but I think overall game balance wouldn't have been hurt by improving the role's chances of winning.
I thought the post that you made calling out Spiffy and Celever, while logically sound, was a really bad play, as it broke your normal way of posting just to call out a mafia that you know is almost certainly not Caesar. If you honestly believed that one of VonFiedler or Serious Bananas were mafia, then you had to believe that Spiffy/Celever were a non-Caesar mafia. From the mafia's perspective, why would you want to come off as leading a bandwagon against one of these players with new allegations? You put a target on your back if your post is right. From the town's perspective, you just broke your posting style and end up looking really suspicious as a result. That post makes you look like you have an agenda, especially if you end up being wrong. It's lose/lose.
Odds are decent that as long as you are alive you can win off of some decent luck in a mislynch, and you can make a judgment call based on how the mafia are doing on whether or not to town side or mafia side as the game progresses. From what the role does know, it does know it needs to be alive in order to win, which I think needs to be the number one priority of the role.
Claiming publicly when you only need 1 mafia dead and one villager mislynch is a possible play as sam pointed out. You could point out that you've been trying to help village and will continue to do so and that wasting you is taking away a lynch from an actual mafia, and say you'll just hope to win along the way. You also could claim survivor, which would be fairly believable midway through the game, which gives you a bit more freedom.
The role also had very few unwinnable scenarios as it gets closer to late game. Caesar's the most likely role to be caught by the watcher especially if an earlier tracker claim happened and a mafia lynch is never something that is out of the picture; odds are that at least one mafia will be lynched during the course of the game, and given you have more knowledge of the set up than most it becomes something you can control. It happened to be hard this game though, as von played fairly well (although I think he should have been called out for how sure he was that jalmont was town - jalmont did nothing at that point to deserve that level of certainty of his town-ness). Watcher will never be "an unlynchable villager" alive at late game with a. his role being by far the most useful info role the village has, b. being one of the few protective roles the village has, c. the mafia having a role cop, and d. no doctor to save him from a mafia kill. There are no roles that could possibly clear a vanilla villager, and either the villager appears so clear the mafia will kill him and refresh the mislynch target or he's an actual possible mislynch target you can push.
So yeah, I think that while it's true that the role could have probably used some slight buffs, it wasn't so bad that it was bad that it didn't have them.