Change

One of the dangers of taking a well established setting, such as Traveller, and making fixes is the cascade of repair.

Fix that one thing and it changes two others, likely breaking them.

So you fix those, those fixes break two more things...

Pretty soon you've changed the assumptions so much it's not the original setting anymore.

It makes you look back and wonder, why didn't I just do this from scratch in the first place?

I've fixed Traveller more than once.  I've also broken it more than once.

Sometimes the players really dug what I'd done.  Sometimes they did nothing but stare at the cracks and complain.

Gods, what all have I done?

Chucking the entire combat system.  This is one of the few times the players were happy.

Changing to GURPS from the OG rules was also popular.  Changing from my homebrew to the official GURPS: Traveller was less popular.

Changing the doubletalk of the drives changed the "Imperial Rome" paradigm of the 3rd Imperium on me more than once.

Changes in the real world of computers gutted several hunks of the rules, more than once!

Changes in the vision of what the future would look like snuck up on me a couple times too.  While cyberware and transhumanism might be plausible commonplace future tech, it's NOT Traveller.  It stands out like a light saber at a Star Trek convention.

Making the Aslan into Kzin is something I think we've all done.

And when all is said and done, I keep coming back to the OG setting and assumptions.  They were elegant.

Yes, the maneuver drive and jump drive chuck that whole physics thing out the window by violating all sorts of basic rules.  What we can say is Traveller is GOOD science fiction in that it makes those changes and sticks to them no matter where the assumption leads.  Even if it gets ugly.  It was at least internally consistent and that's all I've ever asked of a setting.

And yet...  The urge to make it my own is always there.  I always understand when I see someone else making it their own too.