Piano is "simpler" (said the guitar player) because the chords/inversions/arpeggios are the same anywhere on the keyboard, you just have to know the key and the progression. I had a friend who would play along with us in Eb, he didn't bother transposing the keyboard, he would just play the chord progression a half-step down. 

It really is just learning progressions. Most modern pop music is pretty simple. What's tough is when you get into downtuned/Grunge/alternative is a bit more difficult. 

BTW, I am in NO WAY disparaging keyboard/pianists. Im blown away by what they can do on the fly.