It is perhaps a trifle harder on the historical scale, as the variables are far greater as almost no historical event exists in isolation from all other historical events. But even with that, there remain significant inflection points where an outcome which was different, regardless of the surrounding events, would likely have made a significant impact on following events.
And so, in an almost paroxysm of "fun" (or as much fun as historians can have), we will spend a few minutes on the What-Ifs of Anglo-Saxon Britain:
1) Britain does not fall: I list this as a potential item, but it is (among all of them) the least unrealistic. Even if the legions had not departed in the early 5th Century, the Western Roman Empire was still in collapse. Legions in Britain may have held off the onslaught for a bit longer, but ultimately someone would have arrived - even if the legions remained, there would have been no reinforcements.
2) The Anglo, Saxons, and Jutes were not initially defeated: One theory is that the Romano-British were the victim of their own initial successes: had they not defeated and held the Angles, Saxons, and Jutes to a smaller, self contained area, the cultural cohesion would not have developed and the area become thoroughly "germanized". Had the initial invasions pushed through as they did in virtually all of the remaining Western Empire, likely a Germanic elite would have ruled over a Celtic-Romano population much as they ruled over a Gaulish, Italian, or Celtiberian populations - and have been subsumed by it in due time. An Ambrosius Aurelianus may have indeed arisen at a later time - to conquer the invaders, not just stop them.
3) Wessex is not the ultimate reigning kingdom: This one is harder to assess. Certainly during the period of the Heptarchy, Wessex was not the leading contender for power. It was their neighbor Mercia. There were differences in dialect between Mercian and West Saxon Anglo-Saxon and undoubtedly small cultural differences as well. Would a united Anglo-Saxon kingdom under Mercia or Northumbria have looked different, and if so, how?
4) The Viking invasions are successful: At multiple times in its history Anglo-Saxon England was threatened with conquest by Danes or Norwegians - literally up almost to the end of its existence. What would this have looked like? We have a bit of a vision in the North Sea Empire under Canute the Great, but in that case England was only a part of a larger empire. What would a single Danish or Norwegian kingdom looked like, especially if (earlier in history) the Anglo-Saxons had much less of a unified culture?
5) Alfred the Great fails: Later Anglo-Saxon England owes its continued existence to Alfred the Great; had he not pushed back the Vikings at Ashdown or succeeded but been killed, it is likely to say Anglo-Saxon England would look very different and we would not have near the history or records that we do from the simple fact that a unified Anglo-Saxon Chronicle would likely not have been started or exist.
6) Canute the Great does not die early: As we have discussed before, the North Sea Empire did not significantly outlast Canute the Great. Had he lived another 10 or 15 years, how much stronger would the North Sea Empire have been? Could it have weathered a transition of power more successfully and remained whole instead of falling into its constituent parts?
7) There is a direct heir to the House of Wessex upon the death of Edward the Confessor: As you may recall, part of the issue with the succession after Edward the Confessor was that there was no direct heir of age. If Edward had a son or if Edmund Ironside's son Edward had survived instead of dying, there would have been far less uncertainty and concern about the succession. Yes, William the Conqueror may have still tried to invade as he had a small claim on his mother's side, but his reasoning would have been much less persuasive and his cause much more mercenary.
8) William the Conqueror is not successful at invading Britain: This could have taken a number of forms. The weather could have prevented his crossing the English Channel (it was already late in the year, as you recall). William loses the Battle of Hastings instead of winning it. In either case, the Anglo-Saxon power structure would have remained firmly in place.
9) King Harold does not die at the Battle of Hastings: One of the reasons that resistance fell apart after the defeat at the Battle of Hastings was that there was no unifying figure for the Anglo-Saxons: the sons of Harold were untested and young and Edgar Edmund Ironsides' son was the same. Had Harold survived the battle, even in defeat, it is possible he could have rallied resistance in a way no one else could have.
It is amusing, in my off moments, to wonder what a Anglo-Saxon England which was not Normanized might have looked like in Medieval Europe. Would Anglo-Saxon England have invaded Ireland as Norman England did? What would the border wars between Scots and Welsh have looked like. Would England have involved themselves in Continental wars? And culturally, the 12th and 13th Century have little Middle English literature due to the Conquest - what works would we have that were never written?
And perhaps most importantly (for our discussion), without the Norman influence, what would the English language even look like?
I have to admit - and in doing so, admit I am odd - that I find such potential scenarios engaging. A world where we had so much more Anglo-Saxon literature would be a great world indeed.