You can't really base it off that, I'm not saying normals don't matter at all, but you are only seeing about 1% of each players games. For example: I win 95% of the games I play when I'm in a premade whether it's just with friends or guildies it doesn't really matter, I've only been with/against you in games probably 5 times but in that amount of time I've probably played 300~ matches. It's completely random which of those matches you end up in, you could come into 5 where we totally steamroll even against other premades or come into some of the ones where we lose.
That is why I don't think what you see in normals is a good way of judging guilds that do ranked, how they perform in every game in ranked is much more important, atleast in my opinion.
I also played against premades from other servers on the PTS and it felt no different to playing against good premades from our server.