Before you bought it, it was clear that it didn't support v6,
before you bought it it was clear that v7 could have different APIs,
before you bought it, you have omitted tests on a CHR and have not tried to install v7 on another test device
All before you bought it.
And now they certainly can't put it back like in v6 for your software, which more than "third parties" seems to me only yours...
shove the sanctimonious attitude, it does no good for anyone. You don't know my business and I don't pretend to know yours. Customer's that I have to support had a business requirement that required that model to be deployed. Every other API parameter we tested performed the exact same, except /system/health...
Changing an API data format on a widely deployed platform provided specifically for 3rd party software integration is a
horrible practice. It can cause unexpected crashes in other people's software that may or may not be easily or quickly updateable. The reality of your situation is not relevant to the reality of the rest of the population globally. To paraphrase something Normis recently said, the world is quite large, you'd be surprised how much is out there. The fact is changing any part of the API built for 3rd party integration can break 3rd party integration, and because MikroTik does not provide highly detailed documentation outlining changes to the platform that a developer could even know in advance a change was made to a function they call, the only way to find out they made the change is to see your code break after they make a change. Imagine if they decided to just change the WPA handshake or IPSec implementation (which are both a form of an API, as it's built for 3rd party systems to communicate with their equipment for data exchange) because they found a better way and then say it's up to everyone else to update their devices to support the change!
If they want to make an API change maturely and responsibly the correct process is to ensure the default data format remains backwards compatible with existing installations and add the ability to request the data in a different format for developers that want the data formatted differently, or do a total update/rewrite of the API and release it as a v2 with a fully updated library.