Assuming that by this point it's a new republic, and not just a continuation of the war.
Yeah I don't even know how to say "EU" at this point without wondering how that gets received then. Then again some folks always just ignored it anyway.
The way EU fleshed out military hardware was actually pretty solid for the most part though, and something I always liked (in the OT anyway). Evolution was pretty static... the Empire, further tied to its "nazi" roots, was trying its hand at "wonder weapons" much like the Germans did... And so things like the TIE Defender come about and are a big evolutionary step forward (for fighters in the SW galaxy) without being absurdly perfect.
They were working on cloaking technology for larger ships, and stuff, the Darktrooper Project... or in my little stupid Star Wars universe, they were also working on a biological warfare project with this new freaky alien species they'd recovered.
I love the TIE Fighter evolution, but really it doesn't have much pre-ANH you can think of (outside EU again), and I really just don't look at the Prequals as having ships in them that directly tied to the TIE Fighters... The ROTS Jedi fighter had maybe the closest ties, but they're pretty loose still... I'm anxious to see how (and I believe we've seen SOME of how) the TIE Fighters evolve or even simply begin as a new branch/style of fighter... Obviously some simple visual or sound elements don't necessitate that they're related (V-Wing sounds, ROTS JSF cockpit, etc.). A mower and a car both have an exhaust but obviously they're not closely related.
Rebels has that funky squatter winged TIE that looks more like concept art versions of TIE ships. It'll be interesting to me to see what they go with.
I'm equally anxious to see what the Rebels have for fighters, assuming we'll see a more organized military for the Rebels at some point in the toon? The Y-Wing and others are there... what else though? I could see Alliance squads using JSF's for interceptors, or V-19's even. I have a V-19 sitting around with the specific purpose of an Alliance repaint and mods because I just love that ship, and love the idea of the Alliance using them for interceptors if they can get their hands on them.
It's easily up there with the TIE Defender and TIE "Avenger" Advanced for a fav EU ship design of mine.