While I generally agree with Stalker0's points, I think most of the problems are rooted in the objective of having a system that would not overwhelm the average new player with too many options and variables to manage. Nonetheless, because the demand seems to be there, I'm fairly sure that we will see more complex options for advanced players in an Unearthed Arcana-type product in the future.
The reliance on hitting, for example, can be mitigated by having a recharge system for missed powers, but it would require more tracking on the part of the player. For example:
[SBLOCK]The first time in an encounter that the character misses with an encounter power or a non-reliable daily power, he gets a recharge range of

.
Each subsequent time that he misses with an encounter power or a non-reliable daily power, he increases his recharge range by 1, e.g. from

to

.
A character who has a recharge range rolls a d6 at the start of his turn.
If the result of the d6 roll is within the recharge range, the character regains a used encounter power (optional; further tracking required: the character must regain missed encounter powers first) and reduces his recharge range by 1, e.g. from

to

.[/SBLOCK]
Alternatively, you could have a feat like the following, but the player will still have to track how many times he has missed with encounter powers and non-reliable daily powers:
[SBLOCK]
Failure Breeds Success
Heroic Tier
Benefit: Each time you miss with an encounter attack power, you gain a cumulative +2 bonus to damage rolls with at-will attack powers until the end of the encounter.
Each time you miss with a non-reliable daily attack power, you gain a cumulative +1 bonus to attack rolls and a +2 bonus to damage rolls with at-will attack powers until the end of the encounter.
Special: The bonus to damage rolls increases to +3 at 11th level and +4 at 21st level.[/SBLOCK]
Similarly, giving more options to players with respect to powers can be done, but at the cost of complicating the game. This could take a number of forms, e.g. simply not "forgetting" older powers when you gain levels (so a 13th-level character would know four encounter powers from his base class, but would only be able to use three in any one encounter) or using one or more feats to gain additional power choices similar to 3e's Extra Power or Extra Spell.
Actually replacing a daily power with an encounter power may be more problematic. It makes a character's power output much smoother, but reduces his ability to mitigate and recover from encounters which are going against him due to luck, tactical errors, etc. One possible way to manage this is to allow him to access his daily power in a pinch, e.g. by spending an action point.