There is a classic alternate history book, Warlord of the Air by Michael Moorcock, about an alternate world in which, in the absence of World War I, colonial imperialism has continued forever and so most of the world is colonial vassals of a select few empires which, while looking utopic on the surface, are beneath it brutal. It's an interesting book - but on the topic of this thread, I cannot help but think of how a lot of TLs and such on this site are a lot like that book, but with the superficial imperial glory played straight. This site being English-language means that this is typically focused on the British Empire[1] but it is hardly restrained to just that. It is, nevertheless, quite striking that this seminal book seems almost like a critique of many timelines and scenarios on this site, and perhaps it's best kept in mind so "Warlord of the Air But Played Straight" ceases to be such a part of this site's DNA.
Related to this is a strange tendency in timelines and scenarios to Burkean victory - that is to say, a tendency towards monarchical, oligarchical, and aristocratic government seeing total victory at the expense of more free and democratic forms of government. Perhaps I am being unfair - after all, Edmund Burke harshly condemned the British Raj for its atrocities (which he discussed in massive and horrifying detail) while the same cannot be said about his latter-day supporters - but nonetheless it is something I have observed. Always better, to many on this site, to have a monarchy with hierarchical institutions over something freer and more representative, even if that monarchy is (like the Second Mexican Empire) only existed to prop up some brutal act of imperialism, and these monarchies rarely have the same crises that real-world ones (including ones like Britain which were forced to give up power to the people) have to go through; the common people remain a "swinish multitude" largely out of the halls of power, and they never do anything about it. It happens quite often on this site, I think, because both it is easier to model the actions of a few or one person than of many, and also because alternate history appeals to the losers of history such as supporters of aristocratic and monarchical forms of government; not much can be done about it. Still, it's a weird trope.
[1] Before I am inevitably accused of "Anglophobia" again, let me just be clear I have nothing against Britain. I, in fact, quite admire John Lilburne, Thomas Paine, the martyrs of Peterloo, and other Brits who fought for liberty. My enmity is solely with the spirit of imperialism and colonialism, regardless of what country's ruling class may have gone drunk on it.