We don't have to 4e way and create powers, but I think retooling your basic sword attack into something people are going to be excited to do is desperately needed. On this same note, providing choice in how you attack/blast/heal is very important. Things get dull when all you can do is the same attack every turn, for the same damage.
This is a really delicate balance. I can imagine some ways get variety, but only at the cost of really slow play and fiddly complexity. It's not really suitable for a game with more than 1 story teller and 1 player IMO.
The easy things you'd try to do to get variety actually wouldn't get variety. The danger of introducing stunts and maneuvers is that you introduce something that is strictly better than attacking, so it just becomes the same thing you do every round for the same damage. The classic 3.X tripper is an example of this. It's not really an improvement in the sense of greater variety where the character does different things round after round depending on the situation.
Or you take the easy way out, the way 4e did and turn everyone into spell-casters. People don't do the same things round after round because the rules prevent them from doing so. On a narrative level it works, because whens the last time you read a book that explained why the combatants were using the combat maneuvers they chose to use. But in terms of being satisfying choices, I'm not sure it is much better. You here a lot of 4e players complaining about how redundant the progression of abilities are as well.
The standard combats I run turn out to be based largely around my expanded flanking rules, and so feature lots and lots of 5' steps where players jockey for position to maximize the parties flanking bonuses while preventing the enemy from doing the same. There is also some jockeying around switching between defensive and offensive fighting stances based on whether you think that you have the monsters' attention. Typically a melee player will take a very aggressive position where lots of enemies can reach him, then turtle up while players in less exposed positions unload with offensive stances. And the need to rescue endangered or exposed players can provoke bullrushes and that sort of thing. But that sort of interest only works in mass combats and really only when my players are trying to squeeze every drop out of the system. My 'duels', one on one fights between two combatants, are admittedly boring. There is some occasional flashes of interplay depending on the feats you have, but not enough to really make the narrative sparkle and really only rarely unless we are dealing with quite high level fighters who just have options and feats out the wazoo. Like 4e, the combat is mainly interesting in the interplay between allies.
I've considering increasing the number of things you can do in combat without feats in hopes to increase tactical options in a duel, but the problem is that the number of things you can do in combat now without feats is already so high that my players seldom remember all the options that they have and use them - offensive and defensive stances, parries, feints, distractions, trips, sunders, grabs, clinches, circles, pushes, tackles, etc. Add to that the options that come up from having combat related skills like Tactics, Leadership, and Tumble and I think my players are already overwhelmed with choices already.
Honestly, the only solution to this I know that is reliable is just better settings for your combats - regardless of the system you are using. Early on I was being really creative about the combat settings to ensure there were reasons to use alternative tactics and movement. But its really hard to maintain that without it seeming really forced.
Still, there are moments. We recently had a roof top chase where the assassin they were chasing left off a 30' high roof top at full speed in to the back of a manure cart. The player closest behind him blinked on his turn, and then said, "This is probably crazy, but I'm going to jump to, aiming to land right on him before he can leave the cart." (The player's character is a Sidhe rogue, so he has almost no hit points but massive skills.) He clears the distance with a jump then using his own body as a weapon, he succeeds in an improvised ranged touch attack, slamming (all 30 odds pounds of him) into the guy from 30' up. I roll impact damage for both, and the assassin gets really unlucky rolls and takes like 30 damage (the Sidhe only took like 9). So I'm like, "You fly out over the busy street and hurtle toward the ground like a missile, just seconds after the assassin. Just as he's standing up in the back of the wagon and reaching for the rail, you land with both feet on the top of his head. His unyielding neck snaps instantly, while you use the cushion of you legs, his body and ultimately 3' of manure to land gracefully but unpleasantly on the wagon. The driver, turns from cursing the champion*, and turns as pale as a ghost, says, "Blood of the gods above. I didn't see anything masters, just let me leave. I didn't see anything." High fives and shouting all around.
*The champion was mounted and trying to keep up with the chase in the streets, only he failed a ride check and crashed into the wagon the round before.
If you have suggestions, I'd really be interested in hearing them, but the thing is video games are strong at some things that PnP is really weak at. Bookkeeping is one of them.