We determined that in almost every case, a player's turn takes time because they don't know their PC, they don't know the rules, or they aren't paying attention.
Welcome to role-playing games.
Some of my favorite gamers to play with have very little interest in learning the rules, because the rules bore them. Those same players are most likely to try the crazy stunts and imaginative solutions that make for great moments at the gaming table. I'm not interested in a game that deems those players Unworthy and refuses to consider them in the design process.
Some players aren't all that into combat and don't pay much attention after "Roll initiative." But they come alive when roleplaying, and make things fun for everybody. I'm not interested in a game that deems those players Unworthy, either.
And most of the folks I play with enjoy some kibbitzing and joking around. I'm not interested in a game that demands I treat every moment as Serious Business.
Now, obviously there are limits to how much the system should cater to such players. But it should be resilient to them, because they're going to be there, especially when bringing newbies into the game. One player who doesn't know the rules should not slow the entire table to a crawl--and other editions have done much,
much better at this than 4E. I remember one evening when I took my then-3E group and put them through a BD&D adventure. I was the only one who had so much as cracked a TSR rulebook before that night, and it had been almost twenty years since my last BD&D game. Starting level was in the 8-9 range and the party included spellcasters. We only had one copy of the rules for the entire table. And yet they made up characters and we blasted through that adventure at Ludicrous Speed. There must have been a dozen fights,
and chargen,
and exploration,
and roleplaying, in maybe three hours.