Going through the wiki, I've noticed an expansion of the cast section recently, a good example is Movie 18 :
http://www.detectiveconanworld.com/wiki/Dimensional_Sniper
Firstly, all the 'background' characters that don't actually make an appearance or even speak (Gin, Chianti, Korn...). In fact I would think people who look for Gin, Shinichi or Heiji episodes look for episodes in which they appear or at least talk, not for episodes where they just make a background appearance.
Secondly, the cameo characters : fair enough for MG in that case I suppose (and even then...) but does Detective Kurumazaki (does anyone even know him ?) appearing even need to be mentioned in the cast list ?
Thirdly, all the unimportant characters such as Miyuki Tabeta, the aforementioned Detective Kurumazaki or, and the most ridiculous in this case, 'woman'.
I would suggest having a required minimum amount of apperances to be in the cast list and getting rid of the characters who only make a background apparance without even speaking. Otherwise, we have these ridiculously large cast lists which I don't think bring much valuable information.
Any opinions ?