Is R hard to learn? The world is full of things that require innovation. I still think I can time the market, and want to back test my hypothesis.
I didn't find R hard to learn, but I qualify as an Excel power user, data geek, with solid statistics and coding skills. That said, if you are serious about modeling and testing your trading scheme, R will probably find its way into your toolkit. There are lots of (free) resources online and even courses like this one:
https://www.coursera.org/course/compfinance.
I will also add, backtesting is a very narrow (one history) view of the market. You should set up your hypothesis under alternative histories, i.e. monte carlo simulations that include black swans. When you survive the zombie apocalypse with 95% confidence, you have a winner.