Looking at the Wiimpersonator report, it looks like only three channels changed: the system menu, HCUE (the wii menu manual), and IOS59 (which is sort of interesting). Not sure what the changes to the sysmenu are (could potentially affect homebrew), but other than that you should be safe. This wasn't a major "bug gets fixed in every IOS" sort of patch.
One thing I noticed is that 4:3 Virtual Console games no longer appear stretched on a 16:9 TV in 1080p, they now have black bars on the sides. I usually had to force my TV to display in 4:3. This is a welcome change to me. Homebrew Channel is locked in 4:3 with bars now as well, and every emulator I threw at it is the same. Even in Snes9X GX, setting the aspect ratio in the menu options to 16:9 Correction only squishes the image further.
Another interesting point to note is that Wii VC NES games look much sharper on the GamePad and TV vs playing the Wii U VC counterparts. The Wii U versions are blurry in comparison. What's that all about?
Do you have to use a Wii controller even for games that use classic controller??? If so I wonder if the homebrew scene could fix this or if we will have to wait for Nintendo next update....really they get vWii on the gamepad with classic controller on the gamepad and that will rock as then we can play all or Wii VC stuff offTV in our hands including the N64 games adn also stuff like XenoBlade, Last Story, COD BOPS, 007 and other games that support classic controller pro. How does this feature work, is there a key combo to switch down to the gamepad or does the system just now mirror the vWii output to the gamepad at all times?
One other much desired feature was finally included in that they now allow you to output audio thru both hdmi and AV cables....still can't do 5.1 or anything but atleast those using DVI monitors with their wii can have a stereo solution now....plus you can go into a lot of 5.1 or 7.1 with AV and atleast get your subwoofer and psuedo surround plus wii pro logic support...Really makes me mad that Nintendo didn't put a damned toslink port on the thing and support standard 5.1 codec like DTS or Dolby...cheap asses