The issue is that there is always a case to be made for something different.

For English readers, words titles like the "Seven Warlords" or "The Four Emperors" and the "Elder Stars" carry meaning and context in a way the untranslated terms do not.

For example, I don't personally have more attachment to the translations. What am I getting from "Five Elder Stars" that I am not getting from "Gorosei?" It refers to a group and it doesn't have any deeper meaning, at least currently, than a name for them. The same is true for the Emperors, Seven Warlords of the Sea and such. Even if you understand Shichibukai is Seven Warlords of the Sea, it adds nothing to the narrative, just like Turtle Destruction Wave adds nothing to Kamehameha. But I didn't reply to just explain I disagree, since that is just annoying and pointless, but to say the issue is where to draw the line.

I think the way Viz and Funimation (generally) translate shit works well. They'll keep titles like "Aokiji"

Like, what about Aokiji is different than Shichibukai? Unlike the previous titles, where I see no difference in the title, their names actually have a "hidden" meaning. As you may or may not know, Aokiji, Kizaru and Akainu are not exactly random names. They relate to the story of Momotarō, where he eventually befriends a pheasant, monkey and dog. The other part of their name, the color, also plays a role in the remaining two Admirals Fujitora and Ryokugyu.

It goes without saying their colors are blue, yellow and red, with the remaining two being purple (though his name refers to a flower) and green. The first set are all primary colors, which again, is obvious. What is interesting is the two colors added involve combining blue with the existing colors. So red and blue is purple and yellow and blue is green. If you really want to overthink this there are some parallels you can draw from this as well, but that also isn't the point.

All I'm really saying is, some of these unimportant things have reasons behind them as well. There is never going to be a perfect answer, as the people writing it typically think about how it reads over some pointless reference to a story most people in the West won't know or the forethought that Oda might eventually use the color in some way. They're thinking "blue pheasant" and "yellow monkey" don't really match these intimidating characters and it's better left untranslated, even if you miss out on the references that would be more apparent if it was translated. But, don't get me wrong, I can see why the choices are annoying as well, but it isn't exactly a problem that has a simple solution either.