Wilbrand doesn't need any more information than letterbomb, wilbrand does support more firmware versions than just 4.3 though so I guess it does technically need to told if it's 4.3 or a lower firmware in addition to the region. The way you said it makes it sound like a negative, when really the point should be wilbrand works on more firmwares than letterbomb, and can be used without a wifi connection.
Wilbrand was made by giantpune but was originally released by me via Modmii. And it is still available via modmii to this day.
Here's some more relevant info for u from an old modmii changelog
6.1.0 Changelog:
Letterbomb was replaced by Wilbrand. Wilbrand was created by giantpune and he has given ModMii the unique privilege of being the first to use and share Wilbrand. Wilbrand, named after the inventor of TNT, is a discless Wii Message Board exploit, or "bomb" if you will. ModMii users will no longer need to be instructed to manually download the Letterbomb exploit; instead ModMii will prompt users for their Wii's unique MAC address and build the exploit on the fly. Unlike Letterbomb, ModMii will only require a wifi connection the first time it constructs the Wilbrand exploit. ModMii will only build the Wilbrand exploit for 4.3 system menu's; however, Wilbrand is supported on all system menu's from 3.0 to 4.3. The reason ModMii does not offer Wilbrand exploits for system menu's 3.0 - 4.2 is because bannerbomb, another discless exploit, can be used instead and it does not require knowing your Wii's MAC Address. Wilbrand is available on ModMii's Download Page 2 as well as other wizard\guide functions. A big thank you goes out to giantpune for creating Wilbrand and allowing ModMii to share it with the world.
Edit: P. S. Did you know I asked giantpune to develop wilbrand? I mean I didn't coin the name, but I was using letterbomb in modmii at the time and wanted an alternative offline solution and giantpune came to the rescue