Thailand's L-39ZA/ART have no RWR or CM either. And even if they had it, ED's Albatros is the one that flew in 70-80s so that would be irrelevant. They're creating aircraft according to reality, not scifi books.
L-159 has different flight characteristics due to changed engine and construction; armament, fcs, 00 seats, whole cockpit with color MFDs, HOTAS system, HUD, CMS, INS/GPS, slime lights, radar... so it's not really the same aircraft. It's like comparing F-15A and E. Somebody already made a wishlist topic for it but it still wouldn't be "just an upgrade to ZA because it looks similar". We would be talking about standalone product and a few years of development time.