To be blunt, you are using the fact that Wandering Minstrel is a splitter to intentionally ignore the very strong effect it has.
I definitely am! Splitters are that strong.
Plenty of examples of boards you want Minstrel on without even needing a Village. The most obvious one I can think of is Highway / Market (Square), without Copper thinning or draw. You want to play as many Highways and Markets per turn as you can tolerate, but you don't want to trip on all that junk. Folding in a few Wandering Minstrel vastly improves your win rate.
Other examples would be stuff like Vassal or Herald. Herald becomes reliable draw even with hardly any thinning in the presence of Minstrel. Vassal can potentially chain into itself into the next Minstrel, which is pretty cool. Wishing Well and Mystic too.
Like clearly a cantrip minstrel at $2 would be quite good on a lot of boards, as evidenced by many players picking them up for $4 when they don't need more Villages. Topdeck inspection, discarding junk, etc are both very very good.
I could easily come up with way more boards where you want Farming Village without needing the ability to discard green cards. Like, pretty much every board where Farming Village is the only splitter, as well as pretty much every board where Farming Village is not the only splitter but you need so much terminal space that the better splitter pile will run out, as well as pretty much every board where Farming Village is a stronger splitter than another splitter which is present. Compared to your boards, out of which the most obvious one is a 3-card combination (i.e. you're probably not going to see it in a random kingdom during your lifetime even if you play thousands of games) and every other example includes specific cards as well, the ability to split seems at least an order of magnitude more important.
Topdeck inspection, discarding junk, etc are both very very good.
Wandering Ministrels also discards Gold or Platinum which doesn't qualify as junk in my book.
I think that it is weaker than other 4$ villages like Worker's Village or Port.
You definitely want it to discard Gold and Platinum. They might not be junk (although it's a little bit arguable for Gold in some cases), but you don't want to draw them before you've drawn all of your Actions, because otherwise you might not draw all of your Actions. Once you've drawn all of your Actions, you can just reshuffle and draw the Golds and Platinums anyway.
Also, I think that Port is definitely stronger than Wandering Minstrel, but even that difference isn't super big. That's because the main feature of Port still isn't the fact that you're able to gain a second splitter for free, but the fact that you're able to gain the first splitter in the first place. The free Port is just a bonus on top of that.