I don't think it's a form of discrimination so much as how many folks they have on their 'plate' to get landed for that area. My particular area only took a few weeks to get landed from DM, but then on landing day, there were myself, my husband and another couple. That is only 2 couples for an entire afternoon. Now imagine the hundreds and hundreds, maybe even thousands of immigrants that need to be 'landed' in the Vancouver area .... Yep, it will likely take some time to get a landing letter, however I think if folks have not gotten one inside a couple of months they should extend the effort, no matter how much a pain in the arse it is, to call CIC weekly to get an update. There has been at least one case here where the person got their landing letter in the mail in the afternoon and was supposed to be landing earlier that same morning. Things can and will go wrong. Do whatever you need to do from your side to ensure that you keep them moving forward on your information.
Good luck and happy landing!