Why? Because removing classses along with the power sources reduces player options. Which... you know... reduce their flexibility.
You do not seem to be listening. If the campaign world calls for the absence of a particular power source, 4E's power source and role creation allows for them to be removed. This is an increase in flexibility. Does it reduce the amount of options available for players? Of course it does, but then again, so does saying no dragonborn or monks in a campaign also does, but that does not somehow reduce the campaign's flexibility. Do not confuse a reduction of options with a decrease in flexibility. When the elemental, ki, psionics, and shadow power sources come out, must I permit them in my campaigns? Do people normally get this much flack as I am now about "No divine power source" as people get when they say "No psionics"? Somehow I doubt it, yet it is an irrelevant point that is proving the most aggravating on this thread.
I was merely curious if this new elegant design feature of 4E has actually encouraged DMs to design worlds and campaigns without the use of certain power sources, which is now far more possible than it was before. THIS IS INCREASED CAMPAIGN-BUILDING FLEXIBILITY! Yes, you are removing classes and player options (four classes out of an increasingly myriad of others), but there is a clear increase of flexibility in world designing in relation to power sources. Furthermore, the existence of the same role within multiple power sources grants more flexibility in class and power source removal without fear that the role is somehow incapable of being filled.
On the other hand, if you just refluff the paladin to something like 'Ancestral Warrior', describe his supernatural powers as channelling heroes from the past, remove a handful of incontrovertibly 'godly' power and perhaps add a few of your own as replacement... why, that would be very flexible.
Yes, I can easily change the fluff of the divine power source. I realize that! I have realized that even before I made this thread! Why is this even an issue? If my campaign world calls for no divine power source, then why should that campaign design call even be an issue?
An initial question was raised as to why remove the power source and not rechange the fluff? But that is also be completely missing the point, which is that the divine power source is not necessary nor should every power source be reflavored in order to retain everything possible. The primary point of this thread is even that power sources can be removed quite readily without any dire consequence due to existence of classes in other power sources who are capable of filling lost roles. Is this a hard concept to grasp? Trying to make divine classes fit into my campaign world is rather irrelevant to this point, yet this seems to be what people are complaining the most about.
Not saying that everything must fit in. But when it can be done, it should be done. Especially if a class you are about to ban interests a player.
That seems to be the message that people are saying on this thread and thereby completely missing my initial point.
So have DMs actually capitalized on this option of removing power sources? Honestly, I doubt that I will never know, because people are essentially ignoring this question and hounding me on trying to make the divine power source fit my campaign world, which is completely beside the point. And now I regret that I even made this thread.