I've been a buyer/holder from the start. If you look at Tyreek through two years, his ADP/hype have always lagged behind his performance on the field. He wasn't given full credit for his rookie year and even after a top 8 finish last season, he's generally ranked as a WR2 in redraft and a fringe WR1/WR2 in dynasty (despite being just 24). I'm not saying he's a lock for WR1 numbers, but if you've got a guy producing on that level without being valued accordingly then there's little reason to sell. There's an argument that he's a gimmicky fluke, but there's also a compelling argument that he has latent upside beyond what we've seen so far.
If you look at the numbers last season, he finished 7th in the NFL in receiving yards despite finishing just 31st in targets. One way to look at that is to say he hit an unsustainable number of big plays and that he's due for regression. Another way to look at it is that his high per-target production reflects his unique talent and that his receiving yards/TDs will scale along with his targets. He only had 105 targets last season. Antonio Brown had 162. DeAndre Hopkins had 176. What could Hill do with that kind of opportunity? Will he ever get a chance to show it?
That's really the next question with him. Is he just an elite deep threat, a turbo-charged version of DeSean Jackson, or is he going to take the next step and become an all-around reception machine like Antonio Brown? That's where we are right now and I don't really know the answer, but a stance in the middle seems reasonable. Special talent stands out and his deep speed is something that we've never really seen before in conjunction with solid football skills. He's not Randy Moss, Julio Jones, Andre Johnson, or Calvin Johnson, but he's similar in the sense that his raw athletic talent is a constant mismatch no matter who he's up against. He's simply faster than everyone else on the field and so far no one has proven that they can solve the puzzle he presents. With the Chiefs bringing in Mahomes, a guy who is specifically known for his arm strength and deep ball, it feels like this could get very out of hand. I wouldn't go crazy and take him in the top 10, but I think the current redraft and dynasty price points offer decent value. He's ranked below his 2017 finish, yet he probably has upside to do better in 2018.
As for Watkins, he's on his third NFL team in five years. Not a good look for him. He obviously has talent, but even in his best seasons he wasn't as productive as Tyreek, and those seasons were a few years ago now. He's the opposite of Tyreek in the sense that his dynasty/redraft rankings have seemed higher than what his production alone has justified. Name recognition, draft hype, and college performance have kept his name on the marquee even though he has faltered a little bit in the last two years with injuries and inconsistency. He's going to make some plays for KC and could be a good FF WR as well, but if you locked these two in the Thunderdome and made them fight it out for the WR1 role, I don't see why you'd favor Sammy. Dumped by two teams. Injury-prone. New kid in town. He has a lot of strikes against him compared to Hill right now.