I suspect this will be one of the fault lines in the 5e development. Many people really like what 4e did with Wizards, and many other dislike it just as strongly.
I think it is possible to cover both bases, but not at once.
Consider this:
5e retains the At-Will, Encounter, Daily structure of 4e powers, and adds "Always On" and "Conditional" ("Always On" is obvious; "Conditional" powers are ones that you can trigger any time you meet the conditions. For instance "when you score a critical hit, you can...") You'll note that I've removed "Utility" from the list - each of these powers was actually already one of the other times, depending on how it was used... they may or may not be given on a different progression, but they're not really their own category.
Then, you create two classes, the Wizard and the Mage.
The Wizard works basically like the 4e Wizard - he has At-Will, Encounter and Daily powers, he has a limited ability to switch out his Dailies each day, and so on.
The Mage, on the other hand, works much more like the pre-4e Magic User/Mage/Wizard - he has no (or very few) At-Wills or Encounters, but can know as many Dailies as he wishes to add to his spellbook. Each day, he then prepares a subset of those Dailies for use (and can prepare the same spell several times if he wishes).
That covers both camps. (Unfortunately, I doubt the Core Rulebook could incorporate both. The Starter Set certainly can't. Given the need for a choice, I would advocate the Wizard get the nod, as it is the easier class to play.)
Rituals should remain, and should perhaps be expanded. The "Ritual Caster" feat should be eliminated - each ritual should have its own prerequisites, but anyone who can meet those prerequisites can learn and use the ritual. And rituals in general should be easier to use - rather than having an enormous cost for a minor trick, there should be a fairly modest cost. Though there should be some cost to stop the Wizard/Mage simply spamming Knock and rendering the Rogue obselete - perhaps it should cost a Healing Surge (or equivalent), to reflect that using the magic thus is exhausting?