Well, my best advice for you is to use the archive function of this very forum and look through your own posts in the 4E forum from years ago.

That said, from my own memory (having not played 4E for years now),
(1) the basic framework was great, and templates are great, and they should have templated a bit more. For instance, it doesn't help the game that there are easily a dozen "fireball"-type effects, some bigger than others, and some targeting fort instead of ref, or dealing some status condition or whatnot. What 4E does very right is that, if you describe enemies as (e.g.) "eladrin", the players will immediately expect them to teleport all over the place (and they do). What 4E does very wrong is that, if you yell "fireball!", the players will wait for you to explain what this particular fireball does (as opposed to yesterday's fireball).
(2) the biggest issue with skill challenges is probably that they have no way of dealing with items or power usage, and in some situations an item or power is just the best solution.
(3) there are all kinds of issues with items, from option paralysis, to the fact that 90% are vendor trash, to the reuse of "daily" powers by buying copies of cheap low-level stuff, to the christmas tree effect. My experience at least is that 4E plays better and smoother without items (using inherent bonuses).
(4) PPs are great, EDs not so much (well, the fluff is great). This is largely because of what you describe: PPs grant more (and more visible) powers than EDs do.
(5) forced movement is fun! What's also fun is crowd control magic. Or both: use forced movement to bunch enemies together, action point to cast massive crowd control.

HTH.