We looked at the concept of having multiple trims at length and decided that not only would it over-complicate things, but there was ultimately no discernible value in doing so. I will now explain a majority of the reasons why, as I know this question could come up again and I want to address it once.
For starters, lets consider a trim that would keep the MX. So, if you were to only cut all the way up to the top of the MX chip, you'd still have to solder to the GPU traces for the primary bluetooth data lines as shown in the guide. So this ultimate 0.1mm soldering skill cap remains a constant even on the most basic trims. You would also have to solder more wires onto the bluetooth as well to properly support it's MX related functions and potentially some of the components related to that. And also don't forget, this trim would also be cutting off the nice vias available for the SD card slot, so you'd still be soldering to the same resistor arrays.
Then, in supporting this additional trim, you have to completely reconsider fundamental things like the internal voltage layer. Now, what gets disconnected where? What jumpers need to be made? And if your trim is slightly off in a decided "easier" trim, it can change the soldering requirements drastically. We only have complete internal layer data for one revision. This is best demonstrated by the CPU-60, as it came to light early when we initially had multiple trims, that only that revision required 3.3v voltage to be reconnected in a certain spot near the MX chip.
So now we either have to make different trims based around specific revisions, or add a ton of additional picture guides for each little minute difference that has to be accounted for. Not to mention having to work with or around the onboard voltage regulators. That's an additional set of guides as well. And if you're using custom regulators, half of the MX's power-related functions will not work(bye bye "full functionality," you can't use wiimotes to turn the system on and off anymore), giving even more reasons to just rewire the 4 data lines + 3.3v and GND. And again, that's really only if you want the clock.
With these facts in mind, coupled with the fact that the MX isn't a requirement and can easily be reconnected with merely 4 wires, we decided there was no point in other trims. Even the disc drive is well on its way out; very soon we'll have a complete solution and there will be no reason to connect it either.
So in short, the very short list of things gained by supporting other trims, versus the copious amounts of bullshit it would take to support them, made the choice to go with one trim very simple. The guide shows the overall best trim in the best shape that works on the most revisions on the easiest Wii's to get, making the only remaining difficulty the soldering. And a solution is coming for that too.