1. Why is it that the arei miklat were not koleit until after kibush v'chiluk, until after the conquest and apportionment of Eretz Yisrael? The only way a murderer was allowed out of an ir miklat was if the kohen gadol died. A person who killed b'shogeg lived every day with the hope that today might be the day of the K"G's passing. The Mishna tells us that the mother's of the kohanim used to bring treats to distribute in the cities so that those in galus would not daven for their son's demise. Since Hashem had said that the division of Eretz Yisrael would be done by Yehoshua and Elazar, it meant that Elazar would live at least another fourteen years -- anyone sent to an ir miklat before that had no chance of getting out. A person can't live without hope! It's not enough to know that a few years or months down the road things may be better -- a person needs to feel there is some chance of things getting better today.
2. The pasuk refers to the shogeg not leaving ir miklat until the passing of the kohen gadol "asher mashach oso," who was annointed by the murderer. It sounds like the murderer b'shogeg was the one who annointed the Kohen, which makes no sense. The gemara therefore interprets the pasuk to mean, "asher nimshach," the kohen who was annointed (passive voice instead of active). So why, asks the Meshech Chochma, does the Torah phrase things in such a misleading way? He explains that Hashem dictates b'hashgacha pratis precisely how long each shogeg must stay in the ir miklat. One person may deserve to stay there 10 years; another person might only deserve to be there 10 days. Who would be appointed kohen gadol and how long that kohen gadol would live was directly dependent (hence the active voice) on the sentence deserved by the murderer. This is a powerful lesson in hashgacha pratis is. We are talking about the kohen gadol who served all of Klal Yisrael in an enormously important capacity, yet who gets that job might depend on the needs of a single person in ir miklat.