The dividend tax credit is given to Canadian's who receive dividends from Canadian corporations yes. This is why if I have to, I'll tax shelter a US dividend payer over a Canadian one.
However, taxation is simply one element, and there are a lot of elements to taxation as a whole.
It is very difficult for us to speak on individual tax situations for investors, so we really don't do it. There are so many elements to it that we don't know about the individual that it makes it nearly impossible for us to provide any sort of guidance without possibly opening up the investor to making mistakes.
Other income, pensions, etc. are all things that can change an individuals tax situation.
What I will say is I have witnessed many Canadians make suboptimal decisions with their portfolio simply to mitigate taxes. They'll choose subpar Canadian investments over US ones that provide more long-term upside just so they mitigate taxes. The only issue there is they've done so at the expense of returns which would have led them to have more after-tax returns. They've reduced the amount of money they've given to the government, yes. But they also still have less money in their pocket overall.
The currency difference is one that is hard to judge as well. For me, I have a long time horizon. I'm not too worried about currency fluctuations because they tend to level out over longer periods of time. This is kind of why I've suggest that the longer your time horizon the less need for investors to hedge against currency fluctuations. Someone in retirement or even a few years away from it may find a large swing in currency detrimental to their retirement goals and as such they may want to hedge (completely up to them). For someone with.... 20 years left in their investing careers, paying added fees to hedge over that time period where they won't need the capital doesn't seem like something that is going to be beneficial.
Prime example, a Canadian dollar today is worth $0.73. If we fast forward 15 years and the dollar still sits around 73 cents, you've paid fees annually to hedge for something that would have produced a nil result anyways. Whereas on the opposite end of things, if you're in retirement and drawing down on your portfolio, short-term fluctuations in currency can have detrimental impacts on your cash flow at that time.