I'm strongly in favor of giving the parliament the ability to propose laws (directives). Currently only the comission can do that.
The way it seems to work in practice (here at least) is most partisan/normative legislation goes through the lower house upwards
And bipartisan (or broadly unpopular or highly technical) legislation goes from the upper house down
It’s more complicated than that, but a one way flow committee sounds extremely restrictive for meaningful reform
A small number of pathways is a good thing, one lone process is probably not (you risk over fitting on both sides)
Edit: Australian legislation has a lot of flaws, but this multimodal setup from my experience is not one of them
The EU system is also not without its flaws but it's not the worst. Enacting broad, sweeping legislation is cumbersome and difficult which is a feature, not a bug. If we had a more streamlined system we'd probably already have chat control by now.