As good as Macross Plus is, like I said, tragedies are always better. Comedies are fire and forget. Fun whores that you just fling around. Tragedies stay with you. As the current ending, it is not tragic. Guld dies, but the ending is still happy. Isamu and Myung gets to live happily ever after.
Guld's death, in a way, is a good thing. Gets to breath, "Phew, one finally died. The triangle is resolved." It's a happy death, I find.
As for an important character dying, Isamu is a very important character to Myung. That settles that.
If Isamu died, it would've put more emphesis on the importance of each character. You always find that something is needed most after you lose it.
Maybe it's just me. I hated the ending to Equilibrium, and enjoyed things like 1984 and CB.