The more firepower, the better. Handguns are not magic death rays. They are weak, hard to aim, and generally low in capacity. Being someone who was shot by a 7.62 Tok, I am especially critical of lower power bullets with little energy transfer, but accuracy is definitely more important.
The ideal sidearm is one of the only things that's debated more than M16 vs AK, or 1911 vs Glock. There are a lot of opions, and most of them valid. It's just that there are countless variables. Like concealment needs, caliber restrictions (more so in other countries) size and shape of hands, capacity restrictions, recoil recovery time vs power, costs, stupid internet debates, things like that.
So all that being said, I have a couple of thoughts.
Even Larry Vickers, pretty much agreed to be the biggest name in 1911's, has stated that a major weakness of the system is the capacity, and that is with a .45. Personally, I think that 16 rounds of 10mm is a nice basic minimum of firepower, but that's just me.
If you have to carry an itty bitty gun, it's possible that a bigger caliber might be harder to manage under recoil. If you practice with a .22 pocket gun to the point where you can do rapid double tap head shots at a BG target out to 15 feet, you might just be a lot better off with that than a Scandium .57, or a pocket Glock, even though the .22 is a zombie rules gun, and the bigger calibers might drop an assailant with a gut shot.
You mentioned accuracy. That is dependent on a number of things, and that is only a question that you can answer by trying different techniques and practicing all the time. Certainly though it's crucial, especially for a smaller caliber gun with a smaller capacity. That's not to say that you need one hole accuracy at 20 yards, but you should practice to consistently shoot silhouette targets with the amount of accuracy you feel you would need.
In any event, the crucial thing, as Clint Smith has put it, is to be able to run with the gun you've got. Not to day dream about how one day you'll have the best gun possible, or how one day they'll make a gun that fixes your predicaments.
The last thing I'll say is that if I had to carry a 7 round 380, I'd practice as I do with my single stack .45. I'd draw the next magazine with one hand at the same time I drew the gun itself if doing one handed shooting, and I'd definitely spend a lot of time practicing reloads. I'd also try to determine whether it was easier for me to get the maximum speed and accuracy with one handed point shooting or 2 handed shooting, because contrary to Jeff Cooper loyalist beliefs, point shooting works well at short distances you're likely to be attacked at, and without weekly practice. But some littler guns aren't that good at it.
Rant mode off, hope that helped.