Yes, less is more when it comes to training effectively for your goals, for sure, IMO. It really does depends on the individual though, and if you have to spend more than 40-60 minutes resistance training, you're not optimizing your time, IMO, even if going for strength/power gains. As far as fat loss being mostly nutrition - that is true for the general majority of people, but not, and for some training is the predominant deciding factor (I am one of those people, and successfully lose fat regardless of what and how I eat - just ask Sean and he'll laugh as he tells you!) But yes, you CAN lose bodyfat AND gain strength as well, and I often do - those who lose strength when losing bodyfat are often not eating enough, being restrictive and silly with their diet. I know many are not going to agree with me, but experience and knowledge has confirmed all points on multiple occasions (and yes, I have personally experimented with myself to test my theories - for me at any rate, since my body is backwards, upside down and back to front in how it reacts and responds to everything from nutrition to training, LOL).
~Rosie~