This is completely orthogonal, and not particularly relevant. That said, I didn't know this was the case. In fact, I'd assume an unspecified mkfs would complain these days.

1) mkfs is a userspace utility. Its defaults have no consideration for which kernel driver implements this interface; I'd bet a dollar that mkfs has been hitting the ext4 driver for ages. 2) As stated in sister comments, support for actual ext2 filesystems is unaffected. 3) Using a very simple fs by default seems like a good thing. FAT (variants) has survived forever by being dirt-simple, despite its faults. 4) Who in the world doesn't specify options to mkfs? It's one of the few operations that really doesn't have "sane defaults".

Is there a "better" default fs? I dunno. I've looked at a few, but most seem... troubled. So many trade-offs.