Not really - if you want to simplify the game, you do two things:
1) Make the characters simpler
2) Make the monsters simpler
So, once we can see what they do with Monster Vault we'll know if they did step 2, but step 1 is absolutely part of it.
I disagree. The fiddly bits are the intricate interactions between Immediate Interrupt and its difference from Opportunity Attack and Immediate Reaction, etc etc etc. None of that is going away. How many times have I had to try to explain to someone that their Opportunity Action doesn't benefit from their bonus to Opportunity Attack rolls? How many 12 yr olds are going to successfully track marks, conditions, and effects by themselves in actual play?
Now, I don't disagree that SOME of that can be mitigated by ditching most powers that apply effects that need tracking, getting rid of niggling subtleties of mechanics of classes like CC and CS on fighters, etc. That will HELP, but the fundamental complexity is in the application of the (already stated not to be changing) core of the rules.
I have spent a good bit of time over the last 2 years answering questions on the WotC 4e Q&A boards. A lot of the same questions come up here too, just with less frequency. There is an unofficial sticky FAQ/quick answer thread there that is up to something like 269 PAGES, plus the Shaman SC FAQ that is 17 page and the Ready an Action FAQ that is 15 pages and another one that I forget the title of that is 112 PAGES. I have literally cranked up a post count there of over 4,000 posts in a year and I'd say a good solid 75% is answering questions. Heck I've slacked off in the last 6 months, so I was answering between 20 and 30 rules inquiries a DAY solid for half a year.
Now a lot of those were on questions about class features and powers that in theory might largely go away in a cleaner class design, but a LOT of them are the same basic questions week after week asking how interrupts work, how CC and CS works, how does Stealth work (big one), etc etc etc. None of those are going to get much clearer with Essentials. Sure, they may be able to clear up the language some, but without breaking compatibility there's only so much you can do. They can issue a whole slew of errata to try to keep the two versions in sync but the fundamental combat mechanics are simply not that easy for people to grasp that aren't already pretty conversant with RPGs and wargames.
So I still have to wonder just how much more accessible you CAN make 4e. Some, certainly, but enough to pull in tons of newbies (especially kids)? I'm not convinced its POSSIBLE let alone that Essentials will do it. BECMI was a pretty darn simple game, even for its time, and kids could easily play it. 4e Essentials is no BECMI, not by an order of magnitude of complexity.