Out of curiosity, what do you mean by “poorly region changed”?
How would one method be better than another?
A Wii that was originally Korean and poorly region changed often results in 003 bricks. There are 2 ways to prevent 003 bricks when region changing and Modmii implements both methods, but some guides will implement 0, especially older ones
If u originally had a Korean system menu then region change but stay on 4.1 or lower u are safe, but an official update to 4.2 or 4.3 will cause brick. To prevent this you need to preemptively install a custom ios80 (ios60 installed to slot 80) with higher version number than the official version, and same goes for slot 70 if updating to 4.2. Ios60 is the system menu IOS for 4.1, and pretty much works perfectly for all system menu versions.
In other words, if u were originally running a Korean system menu, then region changed, and have a stock ios70 or IOS80 as your system menu IOS u will 003 brick UNLESS you preemptively took the 2nd preventative measure - which is to remove the Korean key from the seeprom using Korean Kii
So to sum up, when region changing away from Korean, ideally u will install a custom ios with high version # based on ios60 to slots 70 and 80 AND remove the Korean key from the seeprom using Korean kii
In order to 003 brick u would have to be running 4.2U/E/J or 4.3U/E/J without a custom system menu IOS based on ios60 and also still have the Korean key in the seeprom (edit: other cIOSs may be able to avoid bricks too but definitely not stock ios70 or IOS80)
003 bricks are easily recoverable (by implementing one or both of the precautions mentioned above) so long as u have priiloader or bootmii boot2 installed, and sometimes other methods work like savemiifrii or bluebomb but are more challenging. Unfortunately official updates typically remove priiloader - yet another reason why offline updates can be safer, as priiloader can be retained when updating via WADs if using YAWM ModMii Edition as your wad manager.
Sorry for the verbose and repetitive post, but I hope it answered your question