Can you solve all the problems in ext4 that NTFS claims to solve? No you cant. I am not saying either of the systems is perfect nor either of them is horrible. They are perfect for the use cases they are designed for. If somebody had a file system structure that was unusual(say lots of small files) to NTFS, I think it was his mistake in treating it as a black box.

You don't need to defragment NTFS either, defragmenter runs in the background. Defragmentation is more an issue of driver and not fs itself, I suspect ext4 does some form of defragmentation itself otherwise I can imagine edge cases that could ruin its day.