Thought I´d chime in with my opinion. Sorry If it seems a little negative.
I haven´t posted on these boards in a long time because I´m a little burnt out with the rules of the Pathfinder game. I still run it but only because I want to complete our current campaign. I have been researching a lot about other games that are lighter on rules and will probably choose one of the retro-clones, if I can find players.
When running Pathfinder, I encounter the following problems often:
During combat, I don´t know what a spell does that a monster in the bestiary is able to cast. Also, I don´t know how a monster´s feat or special combat ability works (e.g. Trample or alike).
Ideally, I would prepare for each combat before the session, reading through all the spells, feats and special abilities. Since I don´t have that time however, I usually use the simplest of attack forms so I don´t have to look it up mid-game. I am often wondering though why not everything I need to run the monster is in it´s stat block.
Out of combat, I´m annoyed by all the details in the skill section. Recently, when Paizo posted the possible revision of the Stealth skill, I thought "why all this detail? It takes loads of time to memorize and it´s plain unpractical to work through during a game session". This is also how I think about many skills.
I have come to ignore higher levels, after being completely burned out by the experience twice. We have settled to play E6 only. Sometimes the members of my gaming group jokingly refer to the old swingy days of when we played higher levels and everyone was frustrated.
These are my main gripes with it. Re-organisation could greatly improve it, but in my opinion, a lot of content could also be simplified (edited?), without losing much of what makes the game great.
About half a year ago I recommended Pathfinder to my brother, a doctor who had previously run a few 3.5 campaigns. He bought the Pathfinder Corebook, but when it arrived at his home he said he was intimidated by how enormous it was. Up until now each time I asked him whether he even looked inside, he said it was too much to digest, working full-time. I feel like my recommendation was wrong but also don´t think he is the target audience for the Beginner Box.