I'm in my late 30's and my group has played all of the editions. I love them all with the exception of 4th. We played it for several months but I just found the combat more aggravating than anything.
You missed a lot. But 4th is a very different game from 3rd and going in trying to play 3rd in 4th is doomed.
It felt very video gamish to me with the special moves and all.
You know what feels video gamish to me? Vancian Casting. The idea that you never actually learn spells. They are merely plot coupons you can use if you've chosen to prepare them. And they allow you to re-write most of your character sheet on the fly with no coherent reason. Powers merely feel cinematic.
To put things even more clearly - with the exception of Jack Vance and clearly D&D derived stories I can not recall one single example of Vancian Casting that isn't pure gamism. On the other hand I can recall many stories where someone has a signature move that they don't always use and they wait some time before using their strongest abilities rather than spamming them.
As a DM it was also hard to keep track of each monsters powers etc.
That's just practice and a statblock. The 4e statblock is about half the length of the 3e one, and the post-MM3 one is better laid out than any previous edition's. (And then we get to the 2e Monster Manual where the stats for the basic creatures weren't actually presented).
And for keeping track, try casting Dispel Magic on a mid level group...
I just remember it was going to be streamlined, but were up to players handbook 3 now, right?
And it's still less complex than 3e. Exception based design means that the options don't add linearly and the DM doesn't even need to worry about most of them. In 3e whenever you added a book with spells in it then the whole thing was available to everyone - that added massively to complexity. In 4e if you add ten classes and twenty builds, that doesn't add much complexity at the sharp end. But does extend the design space of what's possible. (That said, I'm not a fan of the PHB3 - but the PHB2 is wonderful).
DM's guide 2 (which I dont think has any real good DM info compared to the earlier editions)
Are you kidding? The chapter by Robin Laws on player types has more actual useful advice for running a good game than
every single previous DMG combined. Including the ones by Gary Gygax.
And malt vinegar actually IIRC catches more flies than honey.