This is a weird take when the main plot of the first movie was how it was fucked up for Wakanda to isolate itself from the rest of the world to the point that the King would rather kill his brother than try and offer any type of help. Like the villain was born from their active inaction and destabilized the country because he was willing to abuse their traditions against them. Wakanda is a dream location but to call it perfect requires activity ignoring the plots of both movies.
Perfect... and admittedly "Mary Sue" was the wrong choice of words.
"Idealized" might be better? But that was my whole argument, that a core tenant of Black Panther is that Wakanda's greatest weakness is its absolute, dogmatic devotion to tradition, which we see
on screen bleeds into the military. The Dora Milaje specifically eschew any sort of modern weaponry and choose to fight with spears. Granted,
vibranium spears and they are EXCEPTIONALLY good at it, but they're still fighting with spears. And that's how they like it.
Wakanda's military strength makes sense given its nature... they are absolutely god-tier at stealth, recon, infiltration, spec-ops, etc. That's their whole thing. What they have precisely zero experience with is force projection, combined unit tactics, etc. They don't have the institutional knowledge or doctrines to fight an actual war because their very nature did not lend itself to that. Wakanda is designed to be defensive, with what offense they do have being highly specialized infiltration units.
A concentrated, "shock and awe" modern military advance on Wakanda would be an almost out-of-context problem for them which would rely mostly on their defensive shield... which again, might actually be enough. It's perfectly in-line with the universe of Black Panther... nations DON'T attack Wakanda because of all the secrecy, and that threatening Wakanda means the Dora Milaje show up and spear you in your sleep. They know Wakanda has technology beyond our imagination. They DON'T know that they don't really seem to have applied to that to their military.
A bit off of a tangent, but Wakanda's tech advantage seems to quickly be losing its edge. One of their "new" inventions in Wakanda Forever was... an Iron Man suit. That Stark had perfect a decade earlier, and Riri built in a garage (with SCRAPS! *sorry*). We should see in Armor Wars that Stark, Riri, and Shuri aren't the only ones who have made them. That's not even to mention the people casually selling alien tech on the streets, or the inevitable introduction of Latveria and Dr. Doom.
Mind you this isn't to trash Wakanda. I want to see an
even better Wakanda that is able to put aside its traditions and become something greater... something which Wakanda Forever has already set the stage for.