I have a 2016-ish Propel. Around the time the cheaper model like I have still had OEM round handlebars and exposed cables before disappearing to the top of the top tube. I put in a modern aero handlebar and stem that can accept somewhat hidden mech cables and it looks better but not as good as the OEM integrated cables are that are coming out now. You just can't really use aftermarket stuff and compete with full custom OEM integration.
I think in my DIY integration the most glaring difference is that where the stem meets the top tube cables going down, I don't have the little aero rubber spacers that hide those cables from the stem area. But whatever. I like it.