I actually agree that the change made Kelemvor less interesting. But it's canon so there is nothing to be done about it but make a different choice in your personal game.
I generally assume the gods of good are out doing lots of good things even if there are some evil things in the world that they can't or won't address.
I mean, I consider myself a good person who helps the homeless and volunteers at soup kitchens. But am I evil because I'm not out fighting the blood diamond slave trade?
If you were a diamond seller (by which I mean the owner and/or operator of a diamond selling company), and weren’t doing anything to actively and meaningfully oppose the brutal evil of the diamond trade, yes. That would make you evil, in a world that has fairly well defined evil, and where that definition more or less boils down to “brings harm for selfish reasons”.
That’s what is going on here.
The gods need worshippers to be powerful and remain gods. They aren’t in any danger of dying from lack of worshippers, so I’m not going to hear any crap about them needing it to live. We are talking about extra food in the pantry, and more luxury food, not “enough calories to survive”, here.
So, do they help each other stay well fed? Not that I’ve ever seen. Do they help gods with declining worship stay healthy? Not “on camera” AFAIK.
But they do put an existential gun to the head of every single mortal in their sphere of power, and say, “you will worship one or more of us, or you will face utter oblivion.”
That is evil.
They could just as easily offer the souls of the faithful a choice from a list of jobs that will keep them out of trouble. They could guard and maintain the wall protecting the city of the dead. They could be empowered to collect stray souls. They could be employed to make the process of going through the Fugue Plane more efficient. They could do any number of things.
They could also reincarnate such souls, giving them another chance to find a path to faith. This option could be open to all souls, but more strongly encouraged for those who found no home in any faith.
They could even simply be made to choose a realm from a list. “You cannot be a stray soul. You will go one of these ways, and if you cannot choose Kelemvor will choose for you.”
They could even just do what nearly all other settings do and just...not have it be an issue at all. The souls that have no other home could simply stay in the fugue plane until they fade into whatever comes after the afterlife, like in Eberron, or they could dwell there eternal, as in Greek myth. (Hades isn’t a place of torment or punishment, but simply a neutral place where the dead dwell together for eternity)
Instead, if we take the setting at face value, the gods choose to punish those who don’t worship them with eons glued to a wall, and ultimately utter oblivion. Not actual bad people, mind you. Just the people who don’t respect the gods hard enough.
