So wormholes could have a threat level based on activity, that means the more activity there is in a wormhole (site running, pvp etc) then the higher the threat level will be.
This means that sleepers will mobilise and may spontaneously appear on grid to search for scouts or to take advantage of pvp. In combat anoms the site composition may change based on the threat level in the system, the higher the threat the more sleepers will spawn or different ships may appear that makes the site more difficult than its standard composition. Of course this does mean more
Sleepers could also start placing turrets in gas sites when activated as soon as they warp in, the sleepers change in gas sites so they aren’t just frigates and potentially contest the site as its ran or occupied at the highest levels. People who occupy wormholes would have to fight the occasional skirmish of sleepers and they may find their PI chains disrupted temporarily (without losing resources) or other passive activities if their system is consistently at the highest threat level. I’m sure there are other ways the sleepers could engage the players who continuously disrupt their wormhole systems