based on the default fee settings. That being said, this doesn't seem like a bad idea at all...
So, a centralized source would declare a "default fee setting", and any time that source decided to change the default fee setting, there would be a new hard fork released that would change the blocksize calculation?
No. No need for a centralized source to have a default fee setting, Bitcoin Core has it. From there, the fee could be calculated as per OP's suggestion using a method similar to the fee estimation that already exists on the reference client. Or is this impossible to implement?
how about miners determine the fee by voting with the coinbase code thing!
they are already in control as to what fee they require to include your TX, so make them vote and take the mean or avg or wtv of the votes, and use that as the "target fee" and have the block size calculation revolve around that.
Booya we solved it, call the devs!

lmao
That could work, but it would raise again the discussion about "miners already have too much control". And there would be a conflict of interests, I think, as miners profit on bigger fees...
Might as well post this here...
determining the block size by targeting a tx fee limit is the most fucktarded idea I've come accross with so far.
The future of fees is uncertain, and the possibility of having them raise quite a bit causes discussions on this matter... I'd classify ideas like this as extreme, on the limit. Only the future will tell us if these are "fucktarded" ideas

No. I will not sugarcoat these ideas because they are dangerous.
Making decisions on the security of a billion $ network based on targeting a certain transaction fee is the definition of "fucktarded"