Looking for assembly syntax slightly different from mototrolla ?

[psxphill]

I remember I have "occasionally" made mistakes (read bugs) with the motorola syntax ever since I learned it, which is why I was curious about the existence of the alt syntax.

If the idea is to remove mistakes then surely the preferred style would be

immediate: move.w #4,d0
absolute addressing: move.w (4), d0

with an error if you do:
move.w 4,d0

I don't know where the brackets round the number for absolute addressing syntax comes from though.

https://en.wikibooks.org/wiki/68000_Assembly#Absolute_far_addressing

[psxphill]

Probably to maintain an analogy with the address register (i.e. pointer) dereferencing syntax:

I understand why the syntax makes sense. I just can't find any official documentation or assembler that uses it.

I thought it might have been MIT standard, but it doesn't appear to be.

[psxphill]

The '#' would then be enforced superfluous syntax.

Yes, that is entirely the point. If you are explicit about whether it's # or () then it will be more obvious to you if you make a mistake and use the wrong one, using naked numbers opens up the possibility to misread it. Which I thought was the problem you were trying to solve in the first place.