This change was made to avoid a situation where the range of channels being input dynamically would break many setups. Since changing this input changes the actual number of outputs, there is no way to dynamically connect these outputs if new ones are added, and if the number is made less the connections which were made are lost.
This approach of limiting the dynamic input of parameters that change the Input and Output count of actors was made throughout the software, and helped to address a few reported issues/bugs.
How were you using the chan # outputs?
Perhaps this is a case where a macro might be better suited since you can have different settings in each copy.