But Talonbane has also a doubled range 3 defense bonus
Which amounts to +0 green dice against secondary weapons. Fenn's +1 green die isn't a range bonus or agility die so he'll get it no matter what is taking a range one shot at him.
You cannot compare best case scenario of Fenn with worst case scenario of Talonbane. HLC doesn't shot at range 1, so for the enemy to be in range 1 is always number 1 tactic (and autoblaster is rare).
Especially in meta where Defenders are bigger part of the meta, range 3 shots with primary weapon will often be the case (same with T70)
This isn't comparing best case for one pilot with worst case for the other. You have one defensive bonus that frequently gets negated and another that never gets negated. TLT, ordnance, HLCs, and cannons on /x7 Defenders are all extremely common.
Cannons on x7 Defenders should be the polar opposite of common.