I reckon almost any bar can be made to fit comfortably if you have a stem or two to choose from.
I dunno about that, you can compensate for rise quite easily, but most of the ‘fit’ comes from the combination of upsweep and backsweep, and some people s wrists are quite sensitive to it.
Some bars are very ‘flat’ (ie: very little upsweep, like old Answer Pro-Tapers, where as others like Azonic doublewalls had a really odd upsweep.
Same with backsweep, some are very swept, some are very straight. Most of the time you will get used to what you have but I know some people that get wrist pain with overly swept bars, and others that do with straight bars.
You can only do so much with stems and rotating the bars, for some people a change of bar is the only option.
The problem, as mentioned above is working out what you need! And trying your mates bike out is not always a good test a as you need to ride bars for a while to get over the initial ‘it’s all differenty!’ feeling, and you need to try them on your own bike while keeping other factors constant.