With pleasure, MADAM.
First off, those insect wings look terrible. I mean, they're not even cool looking wings like Sephiroth's or Tabuu's. They're small, tiny, cricket looking.
Secondly, that weird thing on his head. What is that supposed to be? It makes his head all elongated and oblong. It's just weird.
watch out i'm about to use the shift key
I'd like to preface this by saying that one of the reasons why I enjoy Cell's design, (In particular, perfect Cell) is because it is a product of editorial telling Toriyama to try harder. The whole reason why Cell transforms in the first place is because Toriyama's editor told him that his first two Cell designs were not cool enough. And you know what? He was right. As much as I like the very inhuman-buglike Imperfect Cell, Perfect Cell is an incredibly good design. I'm not going to comment on Semi-Perfect Cell too much because I feel like the wrong direction was being granted in his design process, but he does share some similarities. Perfect Cell is a result of Toriyama being forced to refine his concept and it is very successful. Toriyama having to redesign and "perfect" his concept gels very well with the whole concept of the villain itself. Usually the transformation device is pretty lazy, but Cell is probably the best example of transformations being used well. Usually editorial interference in most things is fucking annoying but I think this is one of the few cases in which it was needed.
Obviously people have very rational criticisms of the story of the Cell saga (not ones that I really agree with, but rational nonetheless) but I'm talking about Cell from a purely concept art and design perspective.
The wings: The wings work on a conceptual and design level. Conceptually cell is supposed to be a creepy, gross, horrific bug, so he has bug wings. I know you're being glib, but it would betray the entire concept of the character if he had these beautiful angelic detailed wings. I for one, am appreciative of the fact that Cell doesn't have the horrifically cliche anime ~angel wings~. Also, the wings function perfectly on a design level, as they contribute to what I think is one of the coolest silhouettes in Dragonball, which employs an effective use of a triangle motif. This lends the design a really balanced sense of shape harmony, which is something that Toriyama didn't really nail down with Freiza until his final form. Again, S.P. Cell kind of loses track of this, but It's still present:
Of course, inside the form of Cell (in the lines and details instead of the overall shape in silhouette) He uses much rounded shapes that are present in Toriyama's more typical designs. Having a a clear, recognizable silhouette with large, simple shapes allows for interesting detail such as the spots. Also, the silhouette needs to be clear from far away, so in distance shots of Cell fighting or doing something, it reads immediately. Another example of a good use of the triangle motif is the Saiyan Saga, apparent in the Saiyan armor designs and Vegeta and Radditz's hair.
This brings me to your point about the crown. Again, it is a part of the overall triangular motif. It also serves two different design functions: to provide a gestural "flow" of direction that draws attention to Cell's face, and to provide a "rest" area of low detail and large shapes that would contrast with the high detail and small shapes of Cell's face. Luckily, there are sketches that Toriyama has done which perfectly illustrates this, and why having Cell without the crown is less effective:
And yeah, it does look "weird", but that is the whole point! I could also get into how the color choices and patterns are another cool aspect of Cell's design (and why it's part of the reason Perfect Cell is the best out of the three) but this post is already too long and I wanted to address your two points.
I'm also not claiming that Toriyama was actively thinking about any of this, but I think it's pretty evident that great design is just a part of his instinct. While I enjoy GT, this is why the character designs that are not Toriyama's just look sooooo lame in comparison. You can copy the way he draws faces, hands or poses, but you cannot emulate the man's intuition.
