The upgrade is a slightly stunty card that might find a home in any Big Hand Deck. This is more of the same, only slightly stuntier, and best suited for Harvey Walters, for whom it was literally tailor made. So much so that he probably doesn't want to spend the XP on the upgrade. Seekers are usually pretty good at finding clues in less complicated ways, but sometimes you just want to buy 2 clues and keep moving. Niche, but good in that niche.
Reduce the cost to play Extensive Research by 1 for each other card in your hand.
Discover 2 clues at your location.
"...See the wall behind you?"
Veeery niche. A full hand of 8 cards means this costs you 5 resources, maaaybe 4 if you can sneak one in before playing it. The upgrade means it comfortably costs 3, which you could tolerate, but 5 resources, even 4, is too much. The only way to get that down further is to either manically shove your hand full right before playing it or building your deck to accommodate a higher hand-size, and at that point, you're Harvey Walters. Yea, you could argue that there are some cards like Dream-Enhancing Serum that you could play this off of, but in many cases, you'll end up having to sit around waiting for the stars to align before this card becomes affordable, and I just don't think two clues are worth sitting on your hand(s) that long for.
Now you could also add this if you shower your Seeker in resources, then go all out with Extensive Research, Higher Education, etc., and I'd be interested to see a resource-heavy Seeker like that (without using Milan just to keep it interesting ;) ). On average, though, Harvey's really the only one to add this to. And he really does love this card because it plays NATURALLY for him, and that's the ultimate takeaway from this review.
The upgrade, however, is not quite so picky.....