I don't know if the Battle of Hastings is really any more significant than many other events- except for its influence on the evolution of the English Language
The replacement of the Anglo-Saxon system with Normal feudalism. Which in turn meant that England and the British Isles as a whole came more into the sphere of France and became increasingly isolated from Scandinavia.
So instead of Britain developing alongside Norway etc, it became heavily involved in France which later resulted in the 100 years war. Celtic culture may even have survived over a greater area had the north remained linked with Scandinavia rather than becoming anglicised via the anglo-norman court.
Hastings was a pivotal moment in Britain's history.
Suggesting it isn't is like saying the Romans came, they saw, they conquered, they left a bunch of broken **** behind and yes, I typed the asterisks.