4 is better than 5 because of Cersei and Sansa (and Jaime?). I honestly cannot recall anything of interest Dany and Tyrion did in 5.
You're the first person I've heard say this (not knocking your opinion at all, just an observation). Interesting. The focus on Sansa in the 4th book made me want to gouge my eyes out. The 5th book still doesn't hit the quality of 1-3, but was a step up from book 4 imho.
I also have a special fondness for the 5th book as I was able to get it signed by George R.R. Martin in the week it released .