Trading off weekly charts means less maintenance and you'll be more immune from data (news) spikes that us intraday traders have to contend with, but then obviously stops need to be wider and therefore positions smaller to adhere to a reasonable risk profile (all stuff you know already probably).
Price action as I see it, as opposed to traditional technical indicators (mostly lagging oscillators), is just observing the repeating patterns which price makes and exploiting the probability of what price will do at certain levels in those patterns. Similar patterns exist in all time frames, you're right.
In theory, well actually in practice too, it's possible to use these recognizable patterns on any time frame and in pretty much any market. Having said that, and I think someone mentioned it before, some currencies/instruments have a unique way of moving, almost a personality. It's worth spending the time to get familiar with how they move and react, or more the point how traders react!