That is true that the kill effectively turns it into a mafia/town situation, which makes the day game work. However, it's effectively Day 1 (even if it's, say, the third day technically, teh first two days had everyone as 'town'. This is the first day for the mafia/town dynamic and Day 1s are painful for the town to handle (it's power is in supplying the tells that get found out later on). While this would work if the town had multiple days to handle it (removing the '1 day doomsday' effect, which would make a fun game in itself but I like the doomsday mechanic) the town really doesn't have the means to do a regular scumhunt once a kill is made. As such, they are heavily dependent on the investigative skills. The balance, then, is in there being a situation when the town is able to find the killer in most cases and there being a situation where the scum can slip by (with the leaning heavily on town due to Time being heavily anti-town here).
Analyzing.. note that I'm thinking as i'm writing here
There seems to generally be three stages to the game:
Early game: Larger number of players. No patterns to try to figure out on the players. That'll result in players randomly performing their actions.
Mid game: fewer players and now patterns and play styles are showing up. actions are now directed as people are now having a plan in order to win (or at least, not lose)
Last Day: 3 player game at night. Win is basically determined by how well you Trained in order to out block everyone or, if no outright winner there, a guessing game as to who to block and who to kill.
The Last Day is, to me, balanced thanks to the Training system. I was foolish to throw that item out. Just having 6 points (20 points in Train for three days) is more than enough to turn the tide into a full win in your favor. BAH, if your opponents didn't train, ONE POINT is enough to guarantee the win. As such, whoever trains more wins. However, you sacrifice your early game, risking both losing to an earlier successful mafia or simply being NKed. Thus you have to plan to fight for the end game here, opting to balance Blocks (to avoid dying), investigates/tracks (to keep others from winning) and Train (to help you win the end). I can see a person try to do a 100 Train all game but that's similar to someone doing a 100 Kill day 1 and attempting to slip by. In the end, I think I really like the risk and reward and the planning required to pull it off.
So the question comes to how the other games work out: To recap the original rules (officially throwing out my suggestions)
You can Kill with a balanace between keeping below the radar (lower points) and actually making the kill (higher points). Think Price is Right
You can Track: Shows how much into Kill they used (thus both if they tried to kill and the chance they made the kill), or, if strong enough, their target as well
Block: Effectivey stop a person from killing
Investigate: Show all nonkill actions or, if strong enough, show everyone that tried to kill the person.
train: talked about earlier.
Ok, let's say you made a kill for 100 points on someone who no one else targetted, and won. Anyone that tracks you will see that you went all out and that you aimed at the victim: confirmed killer. Anyone that investigates will know you are the only killer: confirmed
In fact, if someone decides to go with a high point Investigate, so long as you are the only target, you will be doomed. At most, 2 people will target the same person, which can be figured out by deduction.
My worry, though, comes in if a person kills another, and there isn't a 100-X track or Investigate
I just can't really see an example of a low-point Investigate doing anything. Yes, you can see that, say, Litia did a Block on PlayerX, but what would that really gain? Litia can still kill the same player so knowing that she blocked doesn't stop that. As such, Investigate seems to be an 'go big or go home' skill. It DOES make an odd situation, though: if you are killing, you will WANT to aim at someone who others will try to hit. It's the only way to dodge Investigation.
Track is pretty useful in any form. Chances are, you'll get to see if someone tries to kill and knowing the power used will give you an idea of whether they succeeded. Meanwhile, if the kill is high enough it's an instant confirm (both in that you get to see the target and, chances are, they succeeded anyway).
Thus I guess my fear is if the players didn't get the killer caught in a track. Investigate right now, is either a direct Stop on any killer or giving information that doesn't lead to any killer at all. Meanwhile, while I imagine there should be a big question of 'where di you use your points' there's really nothing to investigate THAT element. If I, as the killer, say I was blocking X, Y, and Z, and a high level Investigate/track wasn't done on me, there's nothing to say that I'm lying and again, day 1 scumhunting isn't reliable yet by itself. It makes me think that a mechanic for seeing what someone did could feed into that "What did you do" concept.
A few ideas:
What would happen if all blocks and tracks informed the other person. i.e. (person blocked you). No power level, all skills work the same. Without power levels, you couldn't use it alone to track anyone, but it would present a check and balance. For example, if I kill someone and Track you, I could claim I was JUST tracking you. Note that if you did a kill (that didn't succeed) I would have to balance the amount of Track I claim so that it would match the amount of kill you applied (If kill attempt for 50, I couldn't claim a Track of 50 since I'd need to know your target). This would match with another item
You MUST use all of your points. You can't claim that you just didn't use 20 points.
If you investigate, it becomes public knowledge. NOT the result, just that you did it. That way you can't just claim 70 points in investigate after someone else told what happened.
(note you CAN claim that you put all your points in Train, but, honestly, if I knew someone was dumping more Train points than me, I would try to win early and aim a kill at them since I wouldn't have a chance at winning at End Game)
All that with the skills left as is. Low level investigate keeps people from just claiming that they did passive things to dead players and high level investigate ensures that you CAN'T just fling 100 points in kill and hope no one notices. Track and Block are your defensive tools (only for end game? Meh, you can fling small bits of block around and really ruin quite a few killers. It also helps your kill. Instead of doing 30, you can do 20 and fling 10 block. A killer doing 40 would not only lose to you but would also look worse to investigations). Train is if you want to do end game stuff. Meanwhile, you're hoping SOMEONE did an investigate each night.
(yes, the public report of investigate means that if no one did it the killer knows, but.. honestly, that sounds neat in a "OMG EVERYONE PANIC" sort of way. Besides, it feels meh to have an entire plan set up only for someon to say "100 Investigate. Lynch HIM!")