I wouldn't expect it to but, if you are changing from a 2G (GSM) to a 3G (UMTS) phone, you will most likely notice an improvement in signal strength & call quality. Reception has a lot more to do with the strength of the signal coming from the nearest tower. Cell sites in rural areas usually have a much larger coverage area due to the fact that there is less interference from buildings, etc... However, local terrain, trees, etc... will affect reception. If you need to know in advance, call or e-mail Rogers customer service and they should be able to give you an idea of the coverage where you are planning to travel.
Also remember that most network improvements and coverage augmentations will usually be done on 3G as opposed to 2G since just about every new phone on the market today is 3G (and 4G).
Hope this helps.