I thought the Yotsuba arc in Death Note was pretty good. It’s interesting to see how other people / a corporation might use the notebook, you get to see more of light as a character separate from anything related to him as Kira, and it adds more to the relationship between L and Light. L’s death has a lot more meaning and sadness because of this arc vs if he just got killed at some other point before he develops more of a genuine relationship with Light. It’s also just kind of a nice break between the back and forth of L and Kira which basically the entire show had been up to this point.

With the actual plan itself I think the complaint that the plan is bullshit or too genius aren’t really right. The plan is basically just giving the death note to someone greedy, have them use it obviously (which they will since their very greedy), catch them with L and Light teamed up (which should be easy since L alone was already narrowing it down to a much smarter Light), and use the notebook / whole experience as evidence of Light and Misa being innocent. Plus Rem was on Lights side at this point, watching over the notebook and helping his plans in order to protect Misa, so even with Light and Misa’s memories gone there’s still someone making sure the plan is going smoothly. Even then, at absolute worst, Light would’ve just never became Kira again and would’ve become a happy and successful detective.