I was pretty disappointed with how Factorio reworked how fluids worked in the expansion. The old system had its quirks and the new system is obviously more performant, but it throws realism out the window which is a bummer.
The old system was nonfunctional and any base that used lots of fluids (like modded ones, or new space age ones) were constantly running up against nonsensical mechanics.
I don't miss it. I also found Satisfactory's old fluid system (with concepts like sloshing) wildly unintuitive. I'll go so far as to say that accurate fluid dynamics is detrimental to any game that's not about beavers and water table management.