When you reached the high levels of your Armory equipment, HDs lose interest because you can't upgrade everything you have unlocked, much less what you really need, and for what you really need probably you will need to keep playing HDs for 1 or 2 years to get those stuff maxed out...
HDs are now even more hard after the turrets buff, and are a huge wasting of units and alloy. The things are worst when you just upgraded your HQ, and gets frustrated because you can't win the Bronzium anymore, at least until upgrade all your defenses all over again.
As Rebel HQ 9 with defenses Level 8, and Imperial HQ 10 with defenses Level 9, I'm still playing HDs for the Durasteel Crates to get more frags for Turrets while all my structures are maxed out for both acc. It's near impossible to get the Bronzium now, so I neither try anymore.
A Windows survivor now training players and helping squads through the Galaxy!
Imperial HQ10 in "BombSquad18" (Level 49 squad)
Rebel HQ10 / HQ8 in "Ewok_revenge" (Level 50 squad)