It happens pretty often. You choose a song to learn, go through it and notice that some part of it is simply beyond your reach. Or even worse, you spend a lot of time learning first half of the song only to notice that in the second half there is a part that is impossible (or too costly to learn) for you. All this time spent and you aren’t able to finish the song. If you were a classical guitarist there would be very little room to manoeuvre. Classical discipline usually requires fidelity to the musical text. However, since we are playing fingerstyle, which is light music, our reality is more forgiving. Of course some people preach that any changes in the original are bad. But ask yourself this: would you rather play the song you like with couple simplifications or not play it at all?
I firmly believe in compromise approach. Whenever I simplify a song, it’s not because of my laziness. It’s because I know learning it 100% accurate is impossible or it would take too much time that I could use elsewhere. Of course the ultimate goal is to learn a song in it’s entirety. But it’s not always possible or practical for me. I could do it if I spent very long time practising but at the moment I can’t afford it.
Does it mean it’s OK to simplify? No. It’s not OK. Simplifying becomes addictive and if you don’t watch yourself it can become your second nature. An easy way around things you have to work on. So I think a musician should always treat it as evil… It’s just that it’s sometimes necessary and lesser evil.
One last thing. Try to keep track of all the changes you made to the original. Once in a while, check if your abilities have grown to the level at which you can tackle the difficult part. You can also consider creating simplified version for occasions when you want to just play the piece for someone,while patiently practising the difficult original.