Sometimes people treat powers like "buttons" that they just routinely mash over and over again, paying little heed to anything except for the power's effect. For some reason, they never had a problem with this in older editions despite the fact that spells never had default descriptive text until 3rd Edition saw the release of Spell Compendium, while 4th Edition provides it for everything. On one hand I think its true that it draws you out of the immersive qualities of the game if you dont put effort into describing the appearance of an action, but thats not the fault of the edition especially when you consider that the homework was done for you.
Now, this can be especially true for players that just jot down power names and a brief rundown of the effect, or for people playing new classes. For example, its easy to know that burning hands is an area effect that deals fire damage, but what does it look like? That brief description adds an immersive layer to the game that helps spark the player's imagination. If you've played older editions you can guess or assume that it looks like a cone of fire erupting from the caster's hands, but what about more esoteric powers like life tap (artificer) or your glorious sacrifice (dark pact warlock)? In this case its a simple matter of openinig a damn book and reading the description.
Just to be clear, this is not anything new. In any edition players could roll dice and wait until the DM determines the outcome. If anything, powers and their descriptions provide narrative for the context of the action and effect. For example, in 3rd Edition and prior if a fighter makes a melee attack, you would make a roll and if successful roll damage. In the narrative, this strike could mean many things, especially when you consider the abstract nature of hit points and the fact that hit point loss does not always mean physical trauma.
4th Edition takes this concept and adds a foundation to it. If you use tide of iron, for example, we know that you try and attack your foe and then follow up with a shield bash that knocks them back. The exact details are up to the DM and/or players to determine, but at the least everyone gets a starting point to work with if you like to mentally envision the flow of combat. You might smack the monster in the face, causing them to stagger back, or they might have actually dodged your sword swing and the damage comes from the fact that you collide into them with your shield and push them back. Maybe you just charged into them and use the force of the charge to shove them away.
If you're a player who really digs these sort of things, like myself, then really you should have a vague understanding of what it looks like from the get-go. I take this a step further and stylize a lot of my own powers. For example, I had a fey-pact warlock whose teleport effects would make it look like that he collapsed into a pile of rotting leaves and reformed elsewhere, and his eldritch blast was a green bolt of twisting energy with golden motes that looked like swirling leaves.
The problem with me when it comes to combat narrative, is that I quickly grow bored with explaining the results and effects over and over again. In 3rd Edition when Red Jason played a human warblade, it got tiresome describing him cutting goblins and the like in half constantly. I tried to mix things up a bit by having him do other things, like tearing the wing off of a chimera (even though he was using a sword attack), but in the end it was like putting Mortal Kombat finishing moves or Final Fantasy summons on repeat: they're cool the first few times, but quickly get old.
What I do like about the powers is that they help mix things up and provide some diverse ways to describe attacks, but even after it gets old at least players have a nice default image to put into place. For example, everyone knows that when the fighter uses tide of iron, that he is somehow knocking the monster back, even if you dont specifically describe it each time. In the end I think that of all the editions that 4th Edition lends itself most easily to game narrative. You get a ready source of description to spice things up with, even if you didnt care to use it in the first place.