Deinterlacing

Why does the optic flow function not include better deinterlacing methods like bwdif or w3fdif? The current one is very slow and I don't think it does a better job than these do. Also I'm not aware of any plugin that I could use to add one of those. Voukoder does allow deinterlacing filters but it will apply them to the whole sequence and not only to the interlaced clips. Also, there should be the option to choose field or frame based deinterlacing, which currently isn't the case. The list goes on with the never-arriving 2 pass hevc encoding for instance, but that is yet another topic. For now, how do I solve premiere's deinterlacing and are there any plans to improve it? I will post this in discussion because I don't think anyone would read my "idea".