Seeing as how VKLL recorded each tape as he did them direct off the laserdiscs, the only improvement is to get SVHS copies.
I'm not sure S-VHS copies would be much different quality wise given how Laserdisc technology work. It's "just" regular composite video stored analogically on the discs and it can't be outputted in any other way, thus it's not possible to record it with S-Video. You should still be able to get a higher resolution picture recorded on S-VHS tapes but that will only matter if the source material exceeds the 320×480 resolution.
They represent a happy time during an early part of North American Sailor Moon fandom, something that might not happen again.
Also across Europe! :-) VKLL subbed tapes from around here were usually not first-hand copies though as they at least would have to be PAL-converted somewhere down the line.