I agree on having a single curl based module. I started looking at curl module when this module was almost finished, in its core part, with this purpose but, due to the chronic lack of time, the result was that the job on the async module was stagnating beacuse an integration would have meant a deep rework of the code. So we decided to start releasing the module thinking that the integration with other modules can be always done with the help of our wonderful community :)