In the UK we introduced the A* grade as a "solution" to this problem; first at GCSE level (end of compulsory high school, age 15-16) and then at A level (pre-university, age 17-18).

Even that just postpones the problem, as grade inflation continues. I expect we'll see A* * before long, and then eventually grade sheets will look like eBay reviews, and students will just get a star count.

Given the tendency of clustering of grades there is no scale which cannot be compressed. A1, A2, A3 could become A.000001, A.000002... and thus still mean nothing useful.