It's one difference between 2 nd and 3 rd edition rules
Bear in mind, though, that this is based on tabletop D&D and is supposed to simulate the actual rolling of dice.
Personally, I actually kind of like the challenge of rolling a character this way, but I'm probably weird
In the context of IWD, where you have six characters to roll, I can see how it might get tedious, but I don't know, there's just something fun about getting lucky rolls.
And no, you shouldn't get them equal, you should focus on the character having the points where it is important. For example, my fighter will have something like:
Str - 18/99
Con - 18 (19 if a dwarf)
dex - 18 (17 if a dwarf, 19 if an elf)
...and all the rest will be 10.
Or, my mage will look roughly like this:
Int - 18
Con - 14
Dex - 18 or 19 depending on race (a high dex is good for AC)
...and 10 in the rest.
BTW, if this thread doesn't end up focusing specifically on IWD, I am going to move it to RPG Discussion, since rolling characters is quite common to several games covered here at Game Banshee.