I mean you're rank 3,000 and it's early June. Not like you're exactly high legend, which is where balance really matters, and where CW sucks.
You put C'thun in any deck and it becomes tier 4 dude, the list on that report was made by people who didnt bother to try and refine CW. It only took me a couple days to make a list that beats ALL the current popular decks (Shaman, DH, Hunter and Priest, all perfectly beatable).
Thousands of stats dont mean anything if people keep netdecking bad lists, the point here is that CW has a lot of room for improvement, dont need to grind until high legend to make this clear.
Nice deck! Around 2k legend I also use CW as one of my stronger decks. However I find Minefield way Stronger then Slam. Against Face Hunter or Deathrattle Demonhunter it is very likely that it clears 2/3 minions.
I tried Minefield, didnt feel necessary to me, was already very favorable against all aggressive decks. Slam is good in all matchups, you need to draw a lot to make Silas OTK consistent. Which wincons are you using? Feel free to share your list here!