First I have to say, I've not yet experienced the grind in 4e.
I don't know just how many options the other system provides (what system is it, btw?!) but I'd like to point out that in 4e there are several combat options available to everyone at all times: charge, bull rush, grapple, etc.
That's at least as many or more options than are available in e.g. Runequest or Earthdawn (to mention two systems I've played for years).
There's also the (oft forgotten) 'do something cool!' option, when you're out of dailys and encounter powers. A bit of creativity and/or utilizing available terrain features allows you to use non-standard maneuvers that can be more effective than repeated use of an at-will.
DMG Page 42 is your friend!
I think the kind of terrain and the kind of enemies present will the biggest influence on the probability of a grind experience occuring.
Personally, I feel, about the only improvement for 4e combat that was a bit lacking until PHB3 came around has been the lack of skill powers. It would be great if you could pick up more of them, though (i.e. without replacing class utilities)!
I think skill powers is a great idea. It's one of the later 3E options (skill tricks) which I was hoping would be brought back into 4E.
Here's something I've been thinking about since I made my previous post. There *are* plenty of options and choices in 4E, but not all of those options and choices are meaningful. There are times when the system gives me a choice between two things, but one of them is obviously far better than the other; this happens more than I would like for it to. Also, as I mentioned, as an encounter goes on longer, my options dwindle as I use my powers.
To answer your question, the other system I was running was a session of GURPS. Granted, by default it's a somewhat hefty system compared to 4E, but -even considering that- that's not what stood out to me as what allowed for more meaningful choices and less grind. What stood out to me was that every option a player has is available to them at all times as long as their character is physically (or mentally) capable of using those options. This allows for meaningful choices throughout the entire fight.
Speaking of meaninful choices and having all options available at all times, this is an area where I feel Skill Challenges are a fantastic idea, yet they don't quite fit into the system quite right. In a lot of games I've played as a player, I often feel as though I'm playing two different games which are stitched together. When I'm in combat mode, I get to use my combat powers; when I'm in skill challenge mode, I get to use my skills. That doesn't mean that I feel it's impossible to mix the two; however, mixing the two sometimes creates pretty odd results.
An example given in the 4E books is to have a trap which needs to be disabled via skill challenge in an encounter. In theory this sounds like a good idea, but it doesn't work out very well in practice. In practice, this leads to a party member given the choice of spending 4+ rounds not contributing to the fight while his allies are beat upon OR using one action to use a power which smashes the trap. It's a choice, but not a meaningful choice because nobody would ever go with option one unless the GM forces that as being the only viable option. Compare this to the other system where all options are equally available at all times; it's just as viable, just as supported, and just as rewarded for me to attempt any of my skills in any situation. Page 42 of the DMG helps in this regard, but it's also something which needs to be used with caution so as to not invalidate powers and make them less meaningful choices.
I'm not in any way saying 4E is bad. I play pretty regularly, and I enjoy playing, but there are a few things I've noticed about the system as I've gained more experience with it. One of the things I've noticed is that I feel monster design needs some work in 4E; a lot of the homebrew monsters which I create deviate from the suggested creation guidelines. I understand the reasoning behind why monsters are supposed to be built the way they are, but I think there's a better way.
Monster design is again somewhere that I find certain things just simply aren't always meaningful. In later levels, PCs often don't take the attacks of typical monsters seriously. This is part of the grind issue in my experience. There are times when you're limited on options as a player, yet the enemy has virtually no chance of winning. Quite a few rounds of the combat turn into a 3E style slugfest where you're just waiting for the creature to die.
Overall, I enjoy D&D 4E, but there are certain areas of the system which seem not quite there. A lot of great ideas which don't seem as though they are fully worked out yet. In some areas of the game, I also sometimes feel as though there are some very conflicting design ideals which are trying to create two different things at the same time. This isn't bad, and I think it's helpful when designing something to have a variety of ideas, but some of the conflicting ideals create odd interactions with the rules sometimes.
Again, I enjoy 4E. I'll be honest and say there were times when I bashed the system, but that's because I learned that I was trying to do things with the system which it wasn't designed to do. Since then, I've broadened my rpg knowledge and have learned other systems. I now find myself more able to relax and enjoy 4E because I now understand that different systems cater to different styles of game. While I do enjoy the game, and I do understand many of the ideas behind the game, I don't always feel the way those ideas are implemented are up to par. A lot of good ideas are there, but I think it will take some time (and possibly another edition) to fully realize the potential of those ideas.