I think there should be two different kinds of ruins.

Yes... It's a nice idea.

Maybe like this:

- each ruin has 9 levels of excavation

- after completing level 1 you discover what kind of ruin it is (2-3 powerful extinct ancient races (these ruins yeld tech/artifact goodies) and one of an inferior race (these ruins yeld luxury/trade goodies only), the placement of these ruins is semi random (certain parts of the galaxy have significantly higher chance of having certain ruin type)

- after discovering the ruin type you can prioritize (globally), like "Excavate Vorlon ruins first"

- each ancient race's ruins type generate separate "knowledge points", so there are sort of "two trees of upgrades", and you might want to focus on just one type of runins (to go faster to the most powerful knowledge).

So when you find a site, what it does is add a little 3-level tech tree into your research system, with the base node being just "Excavate site on Arturi B". Once that research is complete, you get additional branches for whatever artifacts are there. (So say there are two artifacts there, and you already know what one is, you'd then have a little tree with three nodes, two discovered and one not-yet-understood.) If you research the artifact node, you figure out what it is. (Like that it's a weapon technology, or it's a valuable art piece, etc.) For simple things (like statues), that research is enough and you can use/sell/whatever it. For complicated things (like technologies), you get a third-level node in the tree, and if you research that, you get the scientific/technological breakthrough corresponding to it.

I was thinking, and I think it should work some other way. I mean, there should be some connection with research, for sure, but a whole new tech tree inside research system... I don't know sounds too messy too much (not sure what I don't like there, but somehow it feels a bit wrong to me).

Originally I was thinking of a whole new field of research "Alien" but... didn't like it either :D

I agree with the "more excavation unlocks more goodies" premise. But maybe not exactly technolgies (or not only)? Like if you discover ancient black matter generator you get permanent +10% to research points generated for Energy field of research only? Not sure...

BTW, here is the current Research screen: https://www.facebook.com/PocketSpaceEmpire/photos/a.1518291948449273.1073741828.1518285091783292/1570895763188891/?type=1&theater

maybe it would help (first res.points are divided into fields of research and later you spend these points on techs in each field separately).