We wish to port our WHMCS billing replacement system which supports 3 types of billing per service (prepaid, postpaid, current), variable amount/quantity billing support, multi-service commitment based billing, volume based billing and a few other features to Blesta.
Having to inject code in two places, where there is already a todo to refactor it isn't feasible as it will obviously need to be done again in future. This is the reason why I asked if there was a timeframe.
As for functionality, for module/plugin writers it does have to do with functionality. Replacing/changing/intercepting calls to one class is clean and easy.