This is feature I don't really use, but some of openSUSE or SLES users does. Maybe I'll need it when I will play more with bonding devices.

Hm, feature ...
In fact it brings back functionality that there was already there. But it was done in "hwcfg" files - deprecated configuration files for hardware devices. Now that configuration is stored in /etc/modprobe.d/network. But it's probably not final solution.
Why? because all that options are stored "on one place" but options packaged by driver rpms are stored in /etc/modprobe.d/$driver_name.
Maybe in future I'll change that place or enhance functionality to work on whole directory, but I need some feedback or opinions. Are there any?