Welcome for the change. But I think it would be more useful if you can show calculated fee in the send coin dialogue. When the user input the amount, then it should automatically calculate the minimum fee (COIN * 144 / 250) or when the user click the button. The user can freely adjust the fee as they want in the fee input field.

After they click send, it will give them a warning of the consequence of low fee and then asking whether they want to process payment with low fee. It should send out the transaction no mater what fee they enter. It should give a much higher usability improvement.

Many one should be happy for such change so that you may then ask a pull request then.