Yesterday I ran WotC's November Delve "into the Shadows" with a group of 30+ year RPG vets. Here were the rules:
1. Ability scores. Roll 5d6 and drop the lowest 2. I'd like to watch in case you pull off a full set of 18s.
2. Roles and class selection. This game does not emphasize roles. If you want to play 4 wizards from Warthog's Wizards Academy or a trio of thieves or a coven of cerics you can. See changes to power selections below that make this more feasible.
3. Power selection. This is a radical departure from the rules. You may activate ANY at will, encounter or daily power, even if it does not belong to your class. You are still restricted to the number of encounter and daily powers you are allowed to activate per level. Utility powers must be chosen per class as per the normal rules. Daily powers are per encounter rather than per day.
For example, let's say you roll up a Str 15, Dex 13, Con 16, Int 14, Wis 13 and Cha 13. You want to be a human fighter, so you add 2 to your Str to give you a 17. You have the basic class features, like combat superiority and weapon style talent. However, you can try to cleave one turn and cast magic missile the next. He could also activate a Bastion of Defense and Divine Glow during that encounter.
4. Items. Every class is proficient with all (non superior) weapons, armor and items. Note that most magic items are restricted by armor and type. (For example, in a normal campaign my cleric can wear heavy armor but he chooses hide armor because he wants the Bloodcut property.)
5. Books. I'll have non WotC sourcebooks with new powers to try and I am offering new powers that I have written for playtesting. If you would like to write you own power I will review it for use.
All of these players have tried 4th edition before and most of them have said they do not care for it. They seemed very pleased with this session, with one coming up to me afterwards and saying "I want to settle a longtime discussion we've been having about 4th edition....this is the way they should have done it!"
The game was not substantially slower, and one thing I found interesting is that everyone was eagerly reading through books when it wasn't their turn. They were engaged in thought 100% of the session, always thinking about the next best option for their character.
As a constrast, later that day I went out of town with my wife and her girlfriend to a party to run a Living Forgotten Realms module. This was the first time my wife had played 4th edition, and the first time her friend had ever played D&D. We used the normal rules (not this freeform power selection houserule), and instead of using books I wrote down all the info they needed on a couple of color coded index cards. These two are completely addicted to WoW, and I tried to explain everything in terms of an MMO. They caught right on and LOVED the game. Although they were nervous and thought it might be too overwhelming to learn all of the rules, the simple at-will, encounter and daily powers gave them just enough strategy without confusing them.
So in summary, I had a very fascinating day exploring how the existing rules are perfect for beginner players. For vets who complain that the game feels stale, opening up powers (even just spontaneous selection within one's class) is a good option for adding more strategy back into the game.