Well to be honest portal making wasn't something Sasuke was canocally shown to be able to do at the time. I mean in Gaiden (if you consider that canon) we knew he could but it was never shown. All we can do is speculate that the Boruto movie is what it looks like I suppose.
I'm not bias bcus I followed an already shown feats and not an assumption.
What about Hirashin? That too is space time. Though they don't make portals they also don't create that spiral suction pattern to use it either. Unless you mean the spiral portal pattern is an Uchiha doujutsu trait which would kind of make sense. Now I'm assuming you are considering Gaiden canon as you are using Shin as an example as well, but even in that we never see Sasuke actually open a portal( so far as I can remember. Feel free to correct me if I'm wrong in this) and Sasuke is using a Tomoe Rinnegan to open his portals and not the Sharingan.
Obito travelled to kaguya's dimension how. Did you forget who saved sasuke?
You just proved my point, opening it as a big portal makes it not suck people this is why Sasuke's didn't suck.
And then If I say it can/have an ability to suck people, will you use it here like it was a fact it can perform it?
Wouldn't that be more a chakra thing though? Opening portals takes a lot of chakra out of Sasuke, so all his abilities get weakened as a result, Ninjutsu, doujutsu included.
In the movie that you should watch Sasuke used the black thing in the middel of Kamui that can suck people and cut through things.
