We have to consider how effective a main perk is in relation to a sub perk. And how effective sub perks will be. Also, with re-rolling, you need a special item that it seems that you can only obtain via participating in the Splat Fest, so I highly doubt you will be able to re-roll all your sub-perks to something ideal. And considering how sub perks are random, or at least they seem random (there is the chance that sub perks may be set in stone with certain pieces) I don't think there will be a go-to type of clothing set.
We will also need to determine how effective sub perks are going to be. Considering that you can get 3 sub perks per piece of clothing, and if sub perks don't really do anything noticeable, or if their benefits are so small, then you could very well let sub perks be a thing. Anyways, you probably would end up allowing sub perks, since just because your equipment is one star, you can't really enforce people to use one sub perk because of how you can add additional sub slots to your gear. The good news to this is that you can easily call someone out on their bluff, because if they kill you, you can see their loadout. But I would rather not let a fight break out over cheating and whatnot.
Main perks however, will probably find go-to perks, since their effects are more stronger, and more noticeable. Things such as Ink Saver (Main) might be a huge go-to for a lot of people, as well as Ink Recovery Up. Speed Up perks might also be used a lot. I am curious to see how effective things such as Damage Up and Defense Up are as main perks though. Ink Resistance Up might also be a potential go-to. The good news is that there are so many abilities it may be impossible to get all the ideal ones, forcing people to make decisions as to what they should bring with them.