Ie. You want to play a martial character so you roll up your stats, pick a race, pick your skills and BOOM there's every martial power at your disposal, you only get to pick so many you can use in X amount of time (At will, Encounter, and Daily) but you get more options as to how your character acts.
While conceptually appealing, there's something I dislike about handing out a lot of powers - the fact that players, as they're usually people, have a limited
working memory capacity - you can only keep track of so many things at once. Sure, you can compensate that by making the player memorise their powers better or by listing them - but since characters change a lot, I don't think that's a good way to handle it, because memorising and lists slow down. With a limited set of powers, you have most of your stuff on your mind - because I frankly hate these situations that go along this line: "oh, I forgot I had this power, this could've changed everything!"
It's not fair to punish players for not learning every possible power they have.
However, I do think that 4E doesn't use enough of your memory space on lower leves, leading to monotony easily - the lack of a 1st level utility is most aggravating! Only attacks on 1st level... Not happy with that.
Tying in with my post above, I'd rather try to diversify the powers by giving them out faster than 4E does it (with no traditional multiclassing, frontloading isn't a problem any longer) and making powers more modal - like a
fire spell can produce a fireball or a scorching ray - and so on. But I wouldn't go a lot above the upper limit of known powers, usually.
You could still keep track of them pretty easily - as I totally embrace the use of power cards - but you'd get a lot more variety, add in the interactions with other powers (again, see my post above), the powers could get a lot more interesting that even a limited set of powers has a host of different applications.
Cheers, LT.