TBH it's getting old preaching the high spec (high SNR with good overall specs) unfilmed WP gospel on the interwebz. Some people are skeptical and think it's hype or a sales pitch which is 100% understandable. I was the same way until I bought it and used it. Many of the guys who are anti have never owned it or maybe they looked through it once or twice and probably at a range or somewhere else with good ambient light in which case it wouldn't look all that special.
Where you live can make a big difference too such as city glow or dark skies, big open fields or desert, etc. Almost all of the guys I've seen who went from average thin filmed to high spec unfilmed have been amazed at the difference. To be fair there have been a few who didn't feel it was worth it however I find that to be rare or they had bought unfilmed with lower SNR.
You have to weed through the BS on the internet because there are closet sellers whether they are private sellers or actual dealers using anonymous user names and then you have associates of dealers or hardcore loyal followers who will predictably always recommend what their preferred dealer is selling. I'm not bashing anybody. Simply pointing that out for some of the clueless out there.
To the OP, there is no such as thing as too high spec of a tube IMO other than the price goes up big time for really high FOM because vendors can charge a premium. If what you mean is, is there a certain point where high high specs start to not matter? I'd say probably yes for the average new user and that'd likely be around 30 SNR with good overall specs regardless of filmed or unfilmed but it's very subjective to the individual. Most new users will find mediocre gen 3 to be amazing. Tubes are unique and weird sometimes so it's possible to have lower FOM tubes that are amazing performers. Unfortunately almost all of us don't have the luxury to look through a bunch of tubes until we find the one we like best, so that leaves deciding based on specs like FOM, if we have the choice that is. Many vendors don't give you the choice or hand select and you get what you get not knowing what you'll end up with until it's in your hands. People never used to be able to request specs from most places but that has changed and I'd like to think it's because of info like this being put on the internet. Most dealers hate it, lol.
When it comes to what a good unfilmed SNR is, my experience so far is that 33+ combined with good to great overall specs is phenomenal. 3000 FOM unfilmed tubes will be absolutely incredible because they'll certainly be 72 res meaning 41.66 SNR! I've never looked through a tube with that high of a SNR but I can say that my 72 Res & 33.9/34.2 SNR unfilmed tubes with good-to-great overall specs are the best looking & performing tubes I've ever had and I've owned quite a few thin filmed tubes ranging from 22-31 SNR with good to great overall specs. My current filmed tubes are L3 M890AV GP with unknown specs and they are awesome other than they streak on light sources. Luckily I don't have many at my property so I'm GTG, lol. They're close behind the unfilmed but the unfilmed even with Anvis objectives on moonless nights are significantly better to me. The best way I can describe it is it's the difference between resolving an image immediately or very quickly versus needing more time to figure out what it is. Especially in a low light environment. Sure, using extra IR, a COTI, etc. solves that but it still doesn't change that the unfilmed is better when it comes to only using NV. It's up to you to decide or figure out if this is important enough to you to spend more $$ on unfilmed.