I have no idea why people think that older D&D editions are somehow more intuitive or easier to houserule. They come to the bizarre conclusion that since 3E and 4E had rules for stuff, that you are now somehow utterly incapable of performing actions that dont specifically have rules spelling it out for you. While I think 3E took things a bit too far by having rules for virtually everything (like crafting and professions), 4th Edition provides some good solid advice on about how to accurately peg a task depending on the level of the character and how hard you want it to be.
And you know what? This isnt bad. It provides an easy-to-reference foundation for what players should expect when trying to do something not covered by the rules. This has the effect of speeding up game rulings while also preventing the DM from making a bad call, even unintenionally, since not all DMs are concerned with fucking over their party and actually want to progress a story. Just saying, is all.
I've been very pleased with the Skill Focus articles at Dungeon's Master, as they are all very good examples on how to take a skill and apply it to areas that fall outside the defined function of the skill (for example, using Heal for torture or Endurance for remaining conscious at 0 or less hit points). I think that everyone should read these and use them. A lot.
In all situations, it was very easy to invent a simple task resolution so that there is a chance of failure and so that he can feel like that his choice had actual merit. In the case of the drop kick, it was a Strength vs. AC attack that did unarmed damage and knocked the enemy prone if he made a successful Acrobatics check (hard DC).
Completely on the fly, and allowed him to do something useful and cool. Was it more powerful than an at-will attack? Not really, but it wasnt so weak as to force him to waste a turn in order to do something flashy: he could be flashy and functional at the same time. I could not say the same for 3E and older games, where generally in order to do something like that would likely involve an attack penalty, an opportunity attack, and probably dick for damage assuming it worked.
I think that the open and flexible nature of skills and level-based DCs allows for a lot of interpration and creativity in the use of powers and skills, such as using scorching burst to create a fire or ray of frost to freeze water. Simple stuff like that, that players might not try since the power doesnt explicitely state otherwise. Would this be game-breaking? I dunno, but if a player wanted to use ray of frost to freeze water in a pipe and cause it to rupture, I'd probably call for an Arcana check to see if she could properly channel the necessary magic to make it work.
I'm not a fan of handwaving rolls unless the task itself is fairly trivial. For example, climbing a fucking wall. Its tedious, and if there isnt any real threat involved them I'm not going to waste time forcing them to make a series of simple Athletics checks in order to try and "keep it real". I'll keep the skill checks for the times where it counts. Maybe if they were attacked by a flock of harpies, a gang of ninjas, or...ninja harpies.