Why are you talking about WoW all the time, there are always people you can see and engage with at any time in WoW actually, stop comparing pineapples to lamborghinis ffs. Of course no one expects to see players "any time" when wandering in space, but with a cap at 50 you won't even see anyone in a city.
Then, WoW's sharding works approximately fine when people you see around you are not necessarily engaged with you. What you're saying here is that with the miraculous Server Meshing (which can as well never exist), "there will most likely be some limit on how many players/ships can be in the same area but that will be what the server can handle", which means the guy you're playing with/against may disappear at any point because the server can't handle it anymore ? That sounds great.