Referring to this piece: https://midwestscrub.wordpress.com/2018/12/28/tie-defenders-too-good-to-be-viable/
Error #1: too much bloat. The game currently highly favors efficient builds. OBVIOUSLY, by slapping all the toys on them, they add even more points to half point and situational stuff is not consistent enough. Furthermore, not enough points for the friends.
Error #2: what's wrong with native 3 red dice? Why so much emphasis on the underwhelming secondaries? Juke on 3 reds bites (and favors having the initiative so easily given to you!), which leads into the next point.
Error #3: no mindgames. BECAUSE the defender wants to move fast on its clunky dial, you can use it to corral your opponent. They will naturally try to dodge or attack the predictable position. But a 1 bank evade carries so much power, especially when an initiative juke will make double duty of the evade token.
#4: Outmaneuver us to compete for that slot on a jouster that can juke. Especially with the wording with regard to mobile firing arcs. It is viable on a defender, but it is a side grade, not an upgrade, to juke.
No, they're not a trickshot Blackout with torpedoes. Their cost reflects not their firepower (which can be still augmented by talents), but their role as endgame fear-mongers (hence, the cost is a feature, a la Kylo/Poe). Which also means that they want to endure only ONE SHOT AT A TIME AS LONG AS POSSIBLE TO REPLICATE THIS EFFECT. JOUST AS AN "IMMORTAL FLANKING SLEDGEHAMMER". People sleep on this gem because of flashy toys.
Check out:
Francois Moret's Vader/Rexler (One of few 2 ships successful at Coruscant)
My Soontir/Rexler/Whisper (despite me playing my worst of the tourney on stream)
BitterFig's Delta/Delta/Palp (Holy Moly did I sleep on these I1's until I gave this list a chance! Coordinate before/after the defender is powerful!)