3) Make failure interesting.
Agreed. This is what I was trying to get at in post 23 upthread.
4) And the last. Provoke and encourage movement
Yes. This connects to my comment upthread in post 13, that 4e likes
space.
Another advantage of space and movement is that it helps break down a tendency that I personally haven't experienced (because I use space in my combat encounters!) but that I've seen reported by more than one other poster: namely, the players come up with by-the-book combat strategies where they open with their best powers, focus fire, and experience cookie-cutter combats.
If the enemies are approaching from multiple fronts, and if there are things that are separated on the battlefield but the PCs can't ignore (eg there's a burning house to the west, and a squad of goblin archers to the east), then the players will have to make choices about how to split up the PCs, how to deploy their defenders and protect their squishies, where they should be prioritising offence and where they just want someone to hold the line, etc. And if the geography and threats/challenges are different each time, and the timing of things is different each time, then the answer will be different each time - no simply strategy playbooks, nor cookie-cutter combats.
1 and 2 are equally as important as 3 and 4, but the latter two are more difficult skills to hone and typically what separates an average 4e GM from a + GM.
Harder, perhaps, yet not as hard as all that - at least in the case of (4). My visual imagination is not all that good (my drawing sucks and I have trouble giving directions to a driver when the map is "upside down" relative to the left and right of the car), but I've been able to come up with some pretty interesting combat layouts for 4e. (Even if I do say so myself!)
Which brings me back to
space. I remember
this fight, where the sorcerer PC crashed 50 squares away from the other PCs, being pursued by hobgoblin wyvern-riders. As the other PCs tried to close the distance to help him, a hobgoblin phalanx advanced on their original position, which they wanted to protect (it had a tower they were looting, and valuable books they had piled up on a tarpaulin just outside the tower). So the players
have to split their forces in some fashion, unless they want to either abandon their downed friend, or abandon their tower and loot. And this also creates the tactical question of how the PCs might cover 50 sq quickly (movement powers, clever use of delaying/readying etc), where the archer should go and which "front" he should concentrate on, etc.
And this didn't require anything fancy in the way of terrain, other than "here's the tower", "here're the books", "over there are the ridges that the hobgoblins have marched down out of".
The combat we ran at the opening of
our G2 episodes had a similar character, though with slightly fancier terrain (but drawn up by Gygax, not me) that made verticality another aspect of the space.
I think (3) is harder than (4) - my narrative imagination is (I think) richer than my visual one, but I nevertheless find that achieving (3) is consistently more demanding on me, as a 4e GM, than achieving (4).