[dogscoff]

I mean, on Earth, with today's technology, we can see system after system after system across the galaxy and determine if there are planets there or not.

Well... no. We can spot stars easily enough, and with a few months' worth of detailed observations and calculations we have been able to identify some systems that (probably) have large planets in orbit, but it's certainly not as easy as you make it sound, and we certainly can't build up detailed maps of those systems- we can just detect some of the more noticable bodies.

We still only barely know our own solar system. There are probably tons of planet-sized objects out in the Pluto/charon orbit that haven't been identified yet. I mean Pluto itself was only discovered about 50 years ago (IIRC) and until much more recently it was thought that Pluto and Charon were one planet. And again, these discoveries were based on extensive, careful observations & calculations with thousands of years' worth of sky-studying (ie knowledge of the movements of the nearer planets) behind them.

If we discovered a warp point in Earth orbit tomorrow and sent a ship through it and found a sol-like system, it would take us years just to find all the planets, moons and things and work out their orbits, let alone figure out what the surfaces of those bodies were really like. (ie SE4 conditions & value).

Of course I'm quite happy to accept that future tech will be far more advanced and do all this much more quickly, but I would like the option to play a more exploratory game.

It would also allow us to start player & AI empires from lower tech levels (yubyub) and build them up convincingly into star-faring races.