Never written here before, but as I'm handling a lot of starter's stuff myself right now, I think I can contribute one thing or another. What's following is a wild brainstorming without a claim to be the only eligible option. =)

A really big problem I see: The good about Pathfinder is its level of perfection and detail. If this starter is designed very simple, it won't catch the Pathfinder feeling. But if the starter booklet has 120 pages (as many people are proposing with "real rules" and "all options"), it's nothing like a real starter. Of course, ready-made characters and similar funnies wouldn't be the right way either as this IS in fact the starter for a detailed game!

My approach would be spezialisation. Pathfinder is SO incredibly detailed, it doesn't even need "the four base classes". Three classes with some options are enough, especially if you add a subtle hint like "Well... in the big product there are ELEVEN of these, yes, eleven, you heard right!" Newbies will be intrigued and curious at once. If it weren't for rogue-suckers not wanting to play anything else, I would even go with two classes. ;)

Which classes? Option 1, standard: Warrior, Rogue, Wizard. It's Ok, I guess... But then, isn't Pathfinder something special? Isn't it cooler than D&D Essentials? Think about the Sorcerer (yeah, instant casting and dragon claws are waaay cooler). I suppose it doesn't fit the "tradition", but this product is not for some old guys lamenting about the downfall of D&D1... it's for new players!

Races are not easy, really. I think I would use Humans, Elves and Dwarfs, taking out very special stuff like stonecunning.

Same for the rules: Take out maneuvers (a starter's game works fine without them), all but two or three conditions, complicated moving actions and stuff like that.

Make it cheap. Really cheap. 20$ for D&D Essentials aren't bad, but... 15$ or even 12$ (!!) would be incredible. Include some dice, even if they are cheap material. I don't know about markers, maps and stuff as I'm biased (we're not using them). Perhaps a double-sided mini-map and a few quite generic markers would be a good idea for visualisation. Perhaps not. In the end, markers can't beat WoW. ;) So yeah, let them out.

An idea: Hone the character building down to mainly simple choice chains. Like...

Which class?

*** Fighter? Here are your Attribute, and Skill values - don't forget the race bonus. (Oh, but in the Pathfinder main game you can allocate your own stats!) Next: Choose a huge axe, two swords or big sword and shield (consequences for attacks, damage and AC are explained right away). Now choose two: Power Attack, Toughness, Weapon Focus (or something like that).

You get thick armor and a torch.

Next level: Choose talent Cleave or Improved Initiative. Get 7 HP, 2 skill ranks. (and so on.)

*** Rouge? Choose one rouge talent of two, choose one talent of two, you get the picture.

*** Wizard? You get the following representative choice of spells, perhaps a choice or two. These are your class abilities, choose one of those two metamagic talents.

*** Sorcerer (if that's cooler)? Choose Arcane or Dragon Bloodline. get Powers. Get cantrips, choose two spells of the following four.

Done? Cool. Calculate your Saves. What's your character like? And so on.

Just some wild ideas, of course.

Main content of this post: Be sure about what you want to do - and who is going to buy it. If it's starters, well, make it for starters. If it's roleplayers who want to take a look, 120 pages might be Ok.