On punk being to "small"

[Fallenone]

So I hear/see a lot of talk about punk being to "small" to face certain people such as Ryback, taker, brock, and look like a credible threat to them, I see most of it on the news board saying "wwe creative" thinks that way, but I also see a good amount of fans think the same way. My question is why do the likes of Y2j, Hbk, Rey mysterio, and such get viewed as credible threat but not punk?

I can understand if their character is built that why, but Punk still seems more of a threat to other then someone like hbk or rey