Zaire is a great name. Unique, cool sounding. You know what’s not cool sounding? Democratic Republic of the Congo. MAJOR LAME!
Byzantium is better than both Constantinople (too long) and Istanbul (an ugly word).
Offer up your own name changes that were a downgrade.
Cape Canaveral was renamed Cape Kennedy and then they rightfully changed it back.
For the most part, I think
“Why did the old place shed its cloak?
That’s nobody’s business but the local folk.” 
Aquinnah is a better name than Gay Head, but I still miss having a town named Gay Head.
I always thought Upper Volta was an awesome name for a country. Then they changed it to Burkina Faso.
I prefer Swaziland to Eswatini. I like Z’s.
I always liked the sound of Bechuanaland over Botswana.
All my elementary school Health classes and junior high Biology classes named the part of the heart that is now called the “atrium” as the “auricle”. I like auricle better, it goes with ventricle (the big pump below) and it doesn’t sound like the foyer of somebody’s apartment complex.
Don’t knock “Burkina Faso”, it’s specially funny in Rioplatense Spanish were “Faso” means “Spliff”, “Joint”
Huh, if i had to vote, i would pick Botswana. Easier to say, and kinda of prettier.
I do like the sound of Persia better than Iran
Berlin, Ontario is pithier than Kitchener, Ontario (in my opinion). Plus it goes well with Paris, Ontario and London, Ontario.
I think Tanzania used to be Tanganyika, much cooler.
It’s interesting how many of these are imposed colonial names that were replaced by what the actual people in these lands call their country.
To continue this train of thought, I always liked the name Rhodesia, though Zimbabwe isn’t exactly a bad name, it’s got a Z and the bab sound, which is cool. Rhodesia, though, is such a soft and flowing word, it’s a warm cuddly blanket of colonial exploitation.
Shake, shake, shake
Shake, shake, shake
Shake Djibouti, shake Djibouti 
And it’s really more logical, too–nobody talks about Iranian rugs.
The boringly named Central African Republic used to be called Oubangui-Chari in French, or Ubangi-Shari. Those are the country’s 2 major rivers, so the older name makes sense in terms of geographical features. Central African Republic sounds almost anonymous, while Ubangi-Shari is unique and as a bonus could be the lyrics of a cool song.
There’s a rock in Oregon along the Columbia river that was called Iwash (meaning penis) by the Chinook tribe, renamed Cock Rock by white explorers, and finally renamed Rooster Rock by the prudes. While Cock Rock is objectively the best name, Iwash is good too and much better than Rooster.
Sure, lots of post-colonial names. And even where the actual people in the land are mostly the colonists, not the indigenous people, it’s a popular upgrade to names these days. For instance, I don’t think there were a lot of people referring to “Aquinnah” in Martha’s Vinyard, but when the locals decided they wanted to change the name from “Gay Head”, the old indigenous name was an obvious choice.
Two separate countries – Tanganyika and Zanzibar. Hence the “Tan” and “zan” parts of the current name.
How about Zambia, the other half of Rhodesia? (I do like “Malawi” better than “Nyasaland”.)