A flag should be recognizable from a distance, at any rotation, and mirrored, so you don't have to make two different sides of the flag.
It should ideally be distinguishable from other flags.
Tricolors fucking suck at this. They are the worst thing to come from the french revolution. If only one or two copied them it would be fine, but everyone and their grandma now has a tricolor to represent them. Look at fucking Belgium and Germany
I'm German and I can barely distinguish them at a glance, especially if they are rotated even a bit. Then there's those fuckers who just fucking steal a flag and change the absolute tiniest of details, like Chad's flag vs Romania's flag. Or tricolors that just have one stripe swapped.
Just look at the flags I posted, that's Russia, Luxembourg, Netherlands and France
And I'm just gonna ignore Slovakia, Slovenia, Serbia and Paraguay because they at *least* have some extra thing on there that might make it easier to recognize. Even though that's still a shit approach.
Another thing a flag should do is, if it has details on it, they should be close to the mast (usually left), so the details don't collapse entirely in on themselves when there is little to no wind. See the US flag, the aussie flag, etc. Top left is a good place for special details like that.
A flag should be so simple that a child could draw it and it would be identifiable.
But at the same time distinguishable.
It takes a really creative person to come up with a good flag, hence why 90% of (non irrelevant) countries just steal their flag design, do a pallet swap and call it their OC donut steel
Needless to mention, the stuff mlpol has are generally *not* suitable flags as either it has too many details, it has text, or it looks exactly like a flag that existed before but with slight differences.
Something like >>137867
could be distinguishable, but the RD in the center is too detailed, fro m a distance it looks like a white blob on a mustard stripe on black background.
All the "spread wing alicorn sitting on a round-ish thing" logos we have here are extremely undistinguishable from existing variants, if you just squint your eyes or walk away a bit.
A flag would be cool, but anything we have would simply not work as one.
Done with my rambling for now.