Yeah, we need to see the corruption of the dark side take hold over the years. Not have vehicles representing it in the mix before the emperor takes power. (Nor have it implied they've been 'on standby' to replace the current ones)

The Tie Fighter became a symbol of evil oppression in the OT. What would it become to someone watching chronlogically if they were around in the republic era too? Even if it's on the cusp of the reform.

I think having ships like the jedi starfighters, which are reminiscent of the TIEs without being "evil" is fine! One of the few things Lucas got right. Unlike those fugly supposed X-Wing precursors.

God I cannot convey enough how much I hate those ships, or how little their inclusion makes sense.