"... keep long comments like that in the messages instead of the tile's comment ..."
Why?
It's called Comment, not tile, lots of people seem to be using it for a title of their work but I think that since it's named Comment I'll use it to comment.
I really feel that including lots of information in the comment will help the community here, if everyone does it it will promote a feeling of sharing of ideas and techniques and lead to better art in general.
For example, what do you think is more interesting and enjoyable? a comment saying "By Yo-Yo" or a comment saying "Tile #5. The metal pipe started in my other tile diagonal from this so it was nice to see it again. The tile above gave a virtually unblendable border so I just drop-shadowed it so it seems to float above, I feel I blended the left quite well, and the bottom very well. Another tile I'm very pleased with."?
When you notice that the artist's name is written automatically right after the comment then the first one is totally useless, whereas the second one gives you some insight into what the artist did and what they think of their creation.
Why bother posting a message to say what is going on with my tile when I can put it in what 'I' think is it's rightful place, the COMMENT!
Anyway, that's just my 4c (Australian).