I sympathize with both sides in this situation. I don't think that CIC officers particularly enjoy judging the relationships they are paid to evaluate; and as many people here point out, that judging will always have an element of prejudice towards people who are different from 'expectations' -- the Greek and Turk who marry, the 65 year-old woman and the 40-year-old guy, etc. All CIC has to go on is what seems normal, and most people are much more than that. There are countries where 'love' is a much less important component of marriage, and there is evidence that this doesn't actually work out that badly. I think that the worst mistake is to try and make your application look normal, when it's not -- as someone points out above, accept the strange parts and show instead what is real about it. Couples who are together have a real advantage here -- stay abroad for a couple of years and make CIC realize it's genuine.
A second issue is that the conservative nature of the relationship evaluation impacts women more severely. For whatever reason, it is considered more 'normal' for an old guy to marry a young woman, than vice versa -- I've seen this in SE Asia, where a divorced guy 15 years older than his wife married her, got her a TVA to Canada within 5 months, brought her there, and disposed of their sponsorship with no questions whatsoever. They had had a short Internet relationship and got married within a week of meeting each other. Reverse the ages, and the Canadian woman is going to have more problems. This also applies to the unfortunate OP in the long, argumentative post on a boyfriend in Togo, where the woman's disabilities were going to put her under drastically increased scrutiny from CIC, for a couple of reasons.