Then inform app where sd card is mouted, im not saying they wrong, the problem is true.... but it's not like it's unsolvable to throw whole thing. It kind of reminds me Sony removing Other OS in PS3 without even trying to fix it just because it profitable for themas as they throws support in PS3 Slim and don't want to be concurrent to friendly IBM.
But can be reformatted without much problem, Xbox 360 requires this process to be able to use any external 3rd party storage, so i don't see how this can be problematic for Android, specially for cards that sit there for ages.
And i don't know why you talking that Android does not support FAT32 where support of it it's part of Linux Kernel that Android uses:
Linux/fs/fat/ - Linux Cross Reference - Free Electrons
Linux/fs/fat/Kconfig - Linux Cross Reference - Free Electrons
And even double checked source of android brach of kernel and i don't see those files being thrown out... even some network file system support that you may never hear about like "9p" are still there. It's just matter of compiling it. But hey, we don't want FAT right? it so insecure! Good thing is it not required to even support FAT to format, as Windows does not require to support ext4 not only format it back to FAT or NTFS but actully see the partition
Personally i don't mind that Nexus 4 does not have a SD Card it's not so much pain for me, i agree that not each phone need to have it. But partitioning problem is not unsolvable, many systems deals with it, not only with partitioning but also diffrent path problem which is similar problem in case of Linux, for example in Windows when you change path of templary files suddenly all applications know what to do.... why Android can't do that? So i don't see point of forcing people to think that SD Cards are bad because Google say so, it's Google that needs to fit to customer needs not customers to Google,it's there problem if they don't customers don't like lack of SD cards.... if not then i don't know why people hate Apple so much. Thats just my opinion