Well, it's been 7 years since this bug was opened. Sure, it's not killing anyone. And I assume that the partitioner correctly handles alignment issues for current drives. But still, IMHO, any time software does something other than what you expect it to do, it's broken.
A simple suggestion: just have partman correctly parse KiB, MiB, GiB, and TiB when someone manually enters a partition size. Currently, these generate an error message. Also, on that page, include a short explanation of the acceptable units and their meanings. I'd say it's fine for partman to just always display partition sizes in 10^n units. The only folks likely to care about this are ones doing manual partitioning. It's likely that any such person will understand what's going on when they specify a 32GiB partition and then see 34.4GB in the list of partitions. It also might be handy to include fdisk on the net-install cd, for use in a shell (or ctrl-alt-f2). But that might be a pain, given that fdisk now has its own shared libs. Just my 2c. -Jeff