I don't feel any great hostility towards Vancian casting really. It isn't a bad concept, but in fact the D&D version of it has always had issues. In the original source material the casting was a lot more like what WotC has made noises about for 5e. Each caster had a 'mental capacity' which he could fill up pretty much however he wanted to, many lesser spells, or a few greater ones, or some mix. There was also no such thing as memorizing the same spell several times (it was certainly never mentioned anywhere by Vance). In addition to this expanding your spell book was HARD. Most wizards had a very limited repertoire, being able to cast maybe a dozen spells when they were really experts, often far less. In a given day memorizing FIVE spells was a pretty good trick for a powerful wizard.
Now, maybe five spells is a bit too limiting. OTOH you have ritual magic, crafting, scrolls, etc which could be a lot of the wizard's shtick. If he only needs to cast once in a while in a fight, and has some sort of 'at-will' and the rest of his resources normally go to pre-fight/adventure buffing and cooking up the right potion or whatever to meet anticipated needs, then it could be perfectly cool.
I think the other side of that is casters really should be 'niche'. You don't get to be an "I'm a wizard, I can learn any old spell", instead you get to be "I'm an invoker, I can blast things good. Hold Portal? What's that...".
Clerics in AD&D at least WERE reasonably tame at lower levels, much like wizards generally were. You couldn't craft healing items, had a decent number of spell slots but used 90% of them for healing, and couldn't swap out another spell for healing. Buffs WERE limited to a few rounds and were pretty mild. Bless was nice, but it was only a +1, etc. I think it would be fine though to keep the priest in this sort of power level generally, and again just restrict them to a few niches via domains. You get some leader functionality, including a serviceable amount of healing, some kind of at-will attack/buff, and some utility spells dictated by the domain(s) of your god. If your god is 'healing' well, you can heal pretty darn good, sort of like the 4e pacifist cleric.
I think its perfectly OK to have 'encounter' spells too for all types of casters. Just rule that low enough level spell slots can be regained in a 5 minute rest. Maybe you get N spell levels you can get back in 5 minutes, the actual spells don't need to be classified as encounter or daily. Make the number you get per 5 min go down each time you rest, and then at the end of the day you have to sleep to get yourself back in shape. I'm sure something good can be worked out.
It isn't exactly perfectly traditional D&D Vancian casting, but it isn't any less like Vance's version that the AD&D version was, and if done right it can keep a decent lid on the casters outstripping the rest of the group, yet give them a decent low level experience as well.
As for the druid's other stuff... I think 4e pretty well solved that. WildShape is thematically interesting, but doesn't blow the game up. You get an 'animal' form you can use whenever, and it unlocks your more melee-centered capabilities. Some druids may largely ignore it and mostly cast. Others may specialize in shifting and be pretty darn good melee combatants. Animal companion can be a decent option as well, and again 4e has a decent concept there in terms of having attacks that use the animal, the PC, or both together. It doesn't really matter much if you can have both wildshape AND a companion, there are only so many things you can do in a round and you'll have to split up your options between them if you go that way.