So I've thought about it more.
Here's what really irks me about the random dice plan: we have no way of knowing if the IC is protected on any given night.
I understand that some of you are holding that up as the great thing about it -- that is, if town doesn't know, neither does scum. But, well, it negates the use of the Watcher 100%. It leaves open the IC for possibly dying any night of the game.
I understand the risks in the current version of the color plan. If the random assignment of colors includes three scum, game over.
What's nice is, well, let's do this:
green/red/blue on N1. Blue is town, green/red don't exist (so is therefore scum).
So, scum knows there will be exactly two layers of protection on the IC. They also know that in the next two sets of three, no matter what, the IC is protected by two or more. So, they know for three nights, they can't kill the IC.
That's the big issue, right? This also happens if there's only one scum on the first night. If there are no scum on the first night, the possibility of the IC dying is higher.
Thing is, we catch scum with this plan, and we FORCE THEM TO USE SHOTS.
And here's how: if the watcher is watching the IC, he expects to see exactly 5 people. Himself, the Doctor, and 3 1-shot doctors.
If scum is one or two of those 1-shots, they need to either target the IC or not.
If they don't target the IC: the watcher sees less than 5 targeters.
If they do target the IC: they have to use an action! So, that's the factional kill...and? Roleblocker. If the Goon and the Strongman are stuck in the same group? One CANNOT target the IC.
Once we have that, we can full claim the yoshi colors and catch scum.
Okay, this deserves a longer response. I thought that these things were already clear, but it appears they are not.
1) The problem with the color plan is NOT that three scum might be assigned the same night... I agree that this risk is neglectable. The problem is that scum insta-wins N4 if they still have their Strongman. And if they no kill, there's a 2/3 chance that they will. (actually, it's 3/5 if we consider that Watcher/Roleblocker won't be lynched... there are some problems with that assumption though) Now you may argue that this setup is so much favoring scum that even a 2/5 chance is more than town would usually have, which hey, isn't out of the question. But I've yet to see someone make that argument. Assuming this setup is balanced, the plan is bad.
2) As pointed out, best strategy for scum, if we use the color plan, is probably to not kill anyone (except Watcher/RB/full Doc probably if one of them claims). So they don't mind targeting the IC if it's their turn. What's more, even if some night, there are less players targeting Xerxes than there should be, what benefit do we have? We know scum is among the three Yoshis, BUT WE DON'T KNOW WHO THE YOSHIS ARE. We could do a mass Yoshi claim, but of course that directly conflicts with the color plan, cause once scum knows who's up, they can just roleblock and win.