Yeah, you did cover it, but it keeps coming up so much that I figured that spelling out the process in a "For Dummies" manner might be appropriate. Hmm . . . Ah, you know what? It's 2016. If people can't think to try right-clicking and reading context menus, they must be used to looking up online tutorials for legit everything, at this point. Screw it. Yeah, pointing people to an online converter would be a thing, too. Good point.
Oh, hey, that's a neat trick. More good thinking! Very nice, mate.
Also, just now getting around to commenting on the Wild Shape Options: Holy nutmonkeys, you are the man! It's nice to accommodate so many variants so well.
I've done quite a bit of thinking on the matter, and I've come to the following conclusions:
- It can't be that you inherit the proficiency bonus of the creature without getting the full bonus (i.e. including ability score bonus) because A) it refers you only to the "statistics," the "stat block," not to the Proficiency by Challenge Rating table in the MM, which is more of a background calculation, and 2) Myers or Crawford stated at one point (I can't find where because they do all their crap through Twitter. Ugh.) that it was intended that way: to be understood at a glance. I wish that I could find it to quote verbatim, but the sentiment was that the druid should look at the character sheet, look at the stat block, and simply use whichever is better in any given check or save.
- By the same reasoning, because expertise calculations are already in the stat block, they should be considered as part of the full bonus that you compare against the druid's.
- Applying the druid's proficiency bonus to the to-hit calculation would be silly, as the druid is not proficient with those attacks except via Wild Shape, which gives the creature's proficiency by copying the stat block. If the reasoning is that the druid's proficiency bonus should be used wherever there is a proficiency, the text does not support that stance. Again, the intent is not to do much background calculation reworking.
- Thus, "Only compare based on total number" has to be the by-the-book method of handling Wild Shape and (True) Polymorph. All other rulings are purely houserule territory.
I would suggest making that option the default and perhaps including a note in the FAQ that reflects this conclusion. If someone can reasonably argue otherwise, I'm all ears, but since an option has to be selected by default and you've already coded in all these variants, it just seems right to reason out which one must be the intended form.
Oh, I guess that I should mention this nitpick while I'm at it: "Higher" is the proper term when comparing two options (such as druid's versus creature's prof.); "highest" is only used when there are more than two to compare. It's not often that you hear of the proper usage of comparatives versus superlatives, so it's no surprise that this is easily overlooked.