On the occasions that I take my ISD or MC80, I certainly feel the need to add upgrades. MC80s almost require Engine Techs to have any maneuverability. I also like AP and ECM on them just to they can survive long enough to bring their weapons to bear. XI7s or Heavy Turbolasers all allow them to force through damage that would otherwise just get removed with a defensive token. I put fewer upgrades on ISDs but I tend to give them Hangar Bays and then just a few upgrades to, again, force through damage from that massive front arc.
In all honesty I don't think the MC80 is necessary. Ackbar tends to favor multiple smaller ships and AFs and MC30s are still very combat capable. I think ISDs are more necessary as VSDs have a tendency to get outflanked and have their massive front arc rendered useless. Only half my theorycraft lists use MC80s. Nearly all of my Imperial lists take a single ISD now.
I'm with you there. New Hotness Ackbar screams for lots of units to boost. Sadly you walked away with that cherry ISD so I haven't seen one since!
Throwing upgrades at 110+ point ships. Christmas tree lists everywhere!