Implement Mastery can be kind of weak. I've seen a number of Staff Wizards with 12 Con or ones who never get attacked, Wand Wizards who forget to use their Wand Power and DMs who make them decide to use it even when they'd still miss. In fact, Orb Wizards tend to be the only ones who ever really USE their class feature and have it do something.
You're selling Implement Mastery QUITE short. Of course anyone who has a bad enough build that they are a Staff Wizard with a 12 WIS is going to be gimped, that isn't a problem with the class feature, its a bad build. With a 16 WIS it's an awesome thing to have. With a 16 (or even 18) DEX Wand of Accuracy is one of the best class features in the game, its hands down superior to Action Surge, which is widely considered to be one of the best feats around. Orb of Imposition is actually the weakest of the PHB options. All of the AP options are quite good, though many people don't think a lot of Tome of Readiness. Still, its a valuable class feature and is absolutely on a par with any feat short of Expertise.
Keep in mind, that you get 4 class features in just the first 10 levels of your character. Who knows how many more features you get at higher level. If they continue at the same rate, you'll have 12 class features as opposed to 1 with a normal Wizard at 30.
Let me give the alternate view. All these class features are acquired between levels 1 and 10, after which you get a PP and then an ED, which provide any additional ones. Its speculation either way, but really adding another 12 class features to classes that are supposed to be SIMPLER seems fairly contrary to me.
If the class feature is anywhere near as useful as one of the Wizard's normal class features, you're pretty much ahead of the game. And, frankly, ANY class feature has to be as good as the ability to get +3 to hit once an encounter.
Huh? I can name plenty of class features on various classes that aren't even close to being as good as an encounter +3. That's basically as good as Elvish Accuracy, one of the best racial powers in the game and almost surely the best racial in PHB1.
As for Ritual Casting. Well, that one's subjective. I view it as worthless. But that's coming from playing 2 different home games as well as LFR in which the total number of Rituals cast by any players I've ever seen in the last 3 years is approximately....10.
Really? Being able to brew potions, make magic items, transfer enchantments, strategic teleport, RAISE DEAD (excuse me, worthless!!!???), and even minor ones like TFD and Knock are all worthless? Sorry, I think that's just nonsense.
I'm assuming they won't, given the preview article that said that nothing will change about any of the old classes at all except Wizards getting half damage on a miss with some of their encounter powers.
They didn't say "nothing will change about any old classes" or at least I don't think its meant in anything like the way you are taking it. I think it means that nothing is going to change in the core rules which would suddenly make your class work differently. They constantly errata classes all the time and they've said they will errata PHB etc to conform to the Essentials changes (phrased differently but that's what it amounts to). So I see nothing that indicates they wouldn't errata Spellbook so its consistent across the entire class. Remember, a Mage IS a Wizard, and all wizards get Spellbook, so it would be pretty odd for a single class to have two different versions of the same class power that only differ in such a minor fashion. Heck, I'll even put up a wager on this one.
Well, the class features say that they "make you better at your school". And there are now a bunch of powers that have the Evocation descriptor. I'm going to go out on a limb here and say they give you special benefits when you use powers of your school.
So, basically this means adding pluses to hit, damage, or addon effects. Also, they seem to imply an increase in power to your class feature as you go up levels. Or at least additional class feature choices.
And the standard WOTC design principle is not to give people worthless bonuses so small that you'll forget them(although, I admit, they fail at this design principle sometimes). That makes the class features that you'll be gaining significant in some way....and only getting better than significant as you go up levels.
There are a 100 ways these class features could be balanced. For instance they could be keyed to spells of specific schools as you say. In that case the BOOSTED version of the spell could be basically on par with existing spells. Thus the feature could be power-neutral and yet accomplish the "you get special sauce when you use Evocations" mission. That's only one way that could be sliced and diced. They don't have to be "worthless bonuses" in order to not make the Mage stronger than the Wizard.
Obviously we're going to see when we see it, but I have a sneaking suspicion the designers are cleverer and smarter than you give them credit for.