I'm sure this has been brought up before, but what's with the option of selecting a different type of guest star, but it not making a difference? Whether adding or updating a type, they all show up in the same bag of guest stars. I sincerely don't know what the point is if it doesn't show any kind of difference. Seems kind of... pointless. This is the primary reason why I haven't really started adding guest stars, because I simply don't want to go back and update everything later; I'd rather get them sorted out as I go and move on.
Also, why is Starring not an option? This is applicable in two forms. One is shows that have actors whose names are listed in the first act (after the title sequence), but are specifically not guest cast. Shows like Battlestar Galactica and Millennium are examples. The other kind is usually anthology shows that distinctly credit the guest cast as Starring. And while I'm at it, Featuring is another option that should be added. There are quite a few shows that do make this distinction in the closing credits between this and Co-Stars.