Custom report regarding VAT as per Croatia's regulations

I know that what I am going to ask currently is not possible (at least) because of this but assuming this bug gets fixed what are the chances that the custom report builder gets to a point where both the data and the layout can be customizable?

I am asking with regards to the U-RA and I-RA reports, both available here, that are mandatory both in contents and layout according to Croatian law.

In terms of contents what we are looking at is basically something similar to Tax transactions report, except it is row-wise per invoice: each line is an invoice and has all the tax codes from the left to the right populating only those fields that are applicable.

Since the new Custom Reports are not, and never will be (Custom Report - Data Pivoting), able to pivot data I think that the only way can be through Report Transformation if it will be extended to Custom Reports.

Report transformations (or whatever it will be called in the future) is a mechanism to create country-specific reports. And they will be officially maintained within the program (users won’t be required to create custom reports to meet country-specific requirements).