AbdulAlhazred
Legend
In my own experience, the question this raises is - what are the heroes' capabilities? What can they achieve? Are they mundane mortals? Comic-book/action-movie mortals, like Daredevil or James Bond? Or heroes on a par with the elves of the First Age, or Hercules?
I don't feel that classic D&D does a very good job of answering this question coherently - for instance, the same fighter who can lop the head of a dragon with his sword may have trouble scaling a modest cliff.
I find the 4e mechanical approach makes it easier to answer the question - its genre-led framing (with the players' powers setting minimum parameters of genre permissibility), followed by setting a DC, followed by resolving the action.
To try and cash this out by reference to the giant being pushed: First, a PC won't encounter a giant until they are paragon tier (or perhaps upper heroic for a hill giant). So what the mechanics tell us is that we are playing a game of heroic fantasy in which an upper heroic or pargon shield specialist warrior is so deft and strong with his/her shield that even a giant is vulnerable to being staggered or wrong-footed by his/her attacks. Which already tells us something about the PC - s/he is less like the historical Richard the Lionheart, and more like the lengedary Gawain. And by the time the PC reaches Epic, s/he will be more like (a shield-wielding) Hercules, fighting and staggering titans with his/her might thews and shield.
These mechanically-mandated answers to genre questions also then set the tone for adjudication of non-standard actions, skill use in a skill challenge etc. They set a tone/flavour for what a PC can do.
The game isn't identical to a more descriptor based game like Marvel Heroic RP, but it works in something like the same sort of way, and uses something like the same sort of approach to create the space for, and adjudicate, heroic actions.
I think it is fair to say, as you, [MENTION=23935]Nagol[/MENTION] and [MENTION=27160]Balesir[/MENTION] have all demonstrated in various ways, that 4e has a bit of an odd contrast between built-in PC powers and improvised actions. If a PC uses Tide of Iron then the expectation is that it just works in the same way all the time, the giant is pushed, or the attack misses and things go from there. A page 42 based action would be more in keeping with variable consequences and procedures (IE failure might leave the PC clinging to the railing of the bridge, etc). OTOH if we're expecting appropriate fiction from players when they use powers (or page 42 either) then its less of a problem. Powers work fine, normally, and most of them require no extraordinary narration in the vast number of cases. OTOH if a PC is Tide of Ironing a giant, I'd like a good narration for that, and this can easily lead into some added resolution. It could be as simple as giving the giant a reaction (remembering that while the DM really shouldn't be unfair to the players in 4e NPCs are really tools for doing cool stuff, not absolute descriptions of in-game reality). This is the "rules are tools" position, and is probably quite a bit like the way a 2e fight would work out (IE the DM might well have the giant pick up the PC and toss them off the bridge or etc if the character fails to pull off a stunt). At least in the 4e case the rules for how to do this stuff are quite solid, in 2e it was far less so.