"We need better teaching of fractions" sound like a dangerous cargo-cult solution to the problem of poor understanding of math. If the teaching of fractions would be better, than the understanding of fractions would simply become a worse predictor of long term math success.

The main problem of math teaching is not, that students do not understand fractions (they could easily learn them later), but that they do not understand that math is a (sometimes really helpful) way to think about problems.