Right now writing a little bit than one line (without manual linebreaks) of 
text forces user to manualy set the linebreak.
It would be useful to place large portions of text with the ability to wrap the 
text on the borders of the layer, and automaticaly pass the rest to the next 
line.
Perhaps it would be nice to see Textbox tool in GIMP, which would allow to 
create a box where you type text (separate layer, as it is now is good idea), 
and then after exceeding the right border of the box the cursor would jump to 
next line, visualy breaking it and making.
A good addition to that would be the aility to pass the text to another text 
box, but this is rather complicated.