Too worried about writer issue? That's debatable (4,2,8)

'debatable' is the definition.
(thesaurus)

'too worried about writer issue?' is the wordplay.
I cannot quite understand how this works, but
'about' could be 'on' (as in a book 'on' a certain topic) and 'on' is found in the answer.
'writer' could be 'pen' (something which writes) and 'pen' is found within the answer.
an anagram of 'too' is 'oto' which is present in the left over letters.
This may be the basis of the clue (or it may be nonsense).

'that's' is the link.

Can you help me to learn more?