The issue affects close to every part I ever submit because, like a well-behaved programmer, I comment as much as possible in my files. And after editing a moderately complex but uncommented part recently, I'm very glad I do comment.
So let me summarise the pros.
1) There is minimal hassle in introducing a simple meta like 0 !END_OF_HEADER.
2) Such a simple meta will be parsed correctly by old software, and thus its implementation would not be compulsory.
3) Part authors who use it could add more verbose comments in their files, making re-editing easier.
4) We thus avoid obsfucated LDraw and improve the quality of parts.
On the other hand, for cons we have
1) It is new.
Tim
So let me summarise the pros.
1) There is minimal hassle in introducing a simple meta like 0 !END_OF_HEADER.
2) Such a simple meta will be parsed correctly by old software, and thus its implementation would not be compulsory.
3) Part authors who use it could add more verbose comments in their files, making re-editing easier.
4) We thus avoid obsfucated LDraw and improve the quality of parts.
On the other hand, for cons we have
1) It is new.
Tim