I'm all for A+s to be given out. In the ideal world, this would help distinguish between people -- but it would work best if the rest of the range of grades was thoroughly used, as well. I mean, if a prof only wanted to give out A-s, As, and A+s, that'd be stupid, might as well just give out B+s, A-s, and As, but if a prof actually wanted to buck the grade inflation trend and give out all sorts of marks from Fs to Ds to Cs to Bs to As, then having an extra category of A+ would help expand the range of marks even further.
From a student perspective, I like letter grades, and small ranges of grades, because then I only have to work hard enough to get an A and no harder -- however, if I were an adcomm I'd probably wish that all schools operated on a percentage system, because that allows for even greater differentiation between candidates. That being said, GPA is clearly flawed even for percentages because standards vary so much from institution to institution, prof to prof, that comparing a 87% in a class with one prof in one uni to a 86% elsewhere is impossible, really. Can't say which is better.
But in the ideal world, I think expanding the range of grades to include A+s and utilize the full spectrum of grades right down to F, that'd probably be one of the best. Right now I'm at a post-graduate program that only *can* give 10 different marks (but most end up falling in a range of 3), and you might think that that is more than enough but no, not really. If you have even just 20 essays to mark, chances are that at a certain point you'll wish you could give intermediate, half-X/half-Y marks, and even just as a student I know that if I got Z on a paper and someone else also got Z, chances are there's still a big difference between my paper and his that is just unaccounted for.