Yeah that's the main drawback of the Warp. So not only do you have the four omnipotent deities and either one or two superportals which are their unassailable playgrounds from which they can have their timeless safe spaces, plus the seven super powered Daemon Prince Primarchs (who can't die long term) and all of the assets and daemon hosts therein, but the Warp is probably going to interfere strongly with Star Wars hyperspace travel where it's accustomed to have quick and efficient hyperlane travel between most of the inhabited Star Systems. And added onto that whatever wacky Chaos/Psyker energy fallout that might erupt just from their arrival ala the Eldar near extinction event from the birth of Slaanesh.
It'd have to interact with The Force somehow as well which has always been more nebulous and less proactive as an entity then the Warp has. And it's important to note,
Knights of the Old Republic lore aside, the orthodox view of the Force is that the Force is
Female Light. There is no reference to the Light Side of the Force in the original movies... only the
Dark Side of the Force. Fear. Anger. Hate. Conservatism. Those elements.
Warp Chaos apparently isn't evil... but it seems largely indistinguishable from it.
How the Force and the Warp/Chaos interact will be pretty crucial. Are they even compatible? Maybe a Dark Jedi or Sith can be corrupted by Chaos, but will they be able to call upon the Dark Side of the Force and Chaos/Warp fueled sorcery and powers at the same time? Can the Force be manipulated and used and guided as a shield or inoculate against Warp/Chaos stuff? One would presume so since Versus debates typically work under the understanding that things should operate as they do normally unless there is a good reason for it not to (or else why have the discussion?).
Or if the Warp does come into the Star Wars Universe, what would the effects be of having trilions of trillions of worshippers of decidedly non-Chaos entities. Maybe the Force will become more manifest due to the large number of adherents it has... along with whatever other faiths, religions and ideologies that have enough divine mass to coalesce into potential warp entity manifestation. It'd be ironic if some of the Chaos Gods or their power is consumed/evaporated/subsumed by an explosion of new Force based/Star Wars based entities.
How about if we remove the Chaos gods' ability to directly influece thigs and instead only allow them to guide and give orders to Daemon Primarchs?
That'd probably be more competitive for sure. And in which case if Palpatine is influenced by Tzeentch, poor Magnus the Red will have competition for his Daemon Prince exclusivity to Tzeentch. And honestly, I think Tzeentch would prefer Palpatine more as his Daemon Prince supremo.