ABAP RESTful programming model for brownfield sceanrio

Hi,

We are planning to build an App using the ABAP RESTful programming model. (which we are planning to release by 21 09)

However, while doing initial analysis we have found some limitations, when it comes to numbering, draft etc.

Considering that we are planning to deliver this Apps in a year, is it a good idea to go with the RAP.

OR

Should we just build Apps using the Fiori programming model.

Regards,

Vivek.