I'd say the best ways to represent a siege (I guess you mean something like the Battle at Helm's Deep) are:
- either one or more Skill Challenge(s)
- or gathering of some sort of Victory Points
Skill Challenges
With "Skill Challenge" I don't mean "replace the whole battle with a few skill checks" but rather use a skill challenge as a framework to connect single encounters into a single, massive, confusing, awesome Siege of Doom(tm).
When and how soon did the city learn of the threat and what precautions could be taken before the siege arrived? Can the PCs convince the city's ruler/council to spare some troops (perhaps even clerics or wizards that would be required elsewhere) for a plan the PCs came up with? Do the PCs manage to notice a trap or distraction and find the real attack or attempt to finally break the city?
All these can be answered with appropriate skill challenges, where the outcome of each single challenge determines the next step (and possibly combat encounter) the siege puts in front of the players.
Victory Points
The basic idea is that the outcome of the siege depends on the PCs' actions. The more beneficial actions the players succeed at, the more victory points they gather. The higher their final score when the siege's climax comes around the better the overall outcome (and chances of survival) of the besieged city and its inhabitants.
The DM can award victory points not only based on the result of combat encounters (e.g., whether or not the PCs managed to destroy or sabotage the enemy's siege towers, etc) but also for roleplaying or strategic decisions (Where did the PCs put the city's troops? How did they distribute any magical healing? What are the members of the mage guild supposed to do during the siege? etc.).
Something like this has been used in the official Scales of War adventure path. The first instance such a mechanic is used is in Part 6, The Temple Between:
- If the PCs gather 6 or less victory points, Overlook (a big dwarven city) is burnt to the ground and basically eradicated.
- If the PCs gather more than 6 but less than 15 points, the city is heavily damaged but survives the onslaught.
- If the PCs gather more than 15 points the city survives the siege largely unscathed and with most of its inhabitants and important NPCs alive.
If you want to go with the "stats block" idea, I would not put the whole horde into a single stat block but rather sort the different enemy units into blocks. So you don't have a single elite/solo "monster", but several minion/normal/elite units composed of dozens or hundreds of orcs/zombies/whatever.
This not only solves some of the weird interaction with conditions @AceCalhoon mentioned, but also gives the PCs more possible targets. Do they take out the siege towers to protect the walls? Or do they take out the minion archer squads shooting volley after volley at the defenders? Or do they try to attack the elite siege commander squad that controls the horde?
Best Answer
This is a non-starter. Paladins don't get their powers revoked in D&D 4e, nor are they granted by a god to begin with. If you have your PHB1 handy, turn it open to the Paladin class description and take a look at the paragraph in the top-left of the second page.
In short, Paladins receive their powers through training, an initiation rite, their boundless faith, or so on. Once the Paladin has started down the path of being a Paladin, their powers are their own and are theirs to keep. They are not granted daily by a god, but simply the Paladin's own, as an expression and manifestation of their faith. They cannot be revoked any more than a Sorcerer can be robbed of their spells or a Rogue can be robbed of their ability to smuggle knives into peoples' faces. (For the record, the same applies for Clerics and other divine classes.)
This is a pretty significant departure from previous editions. Another significant departure is that the Gods are distant and mysterious, and generally not concerned with interacting with mortals. Mechanically, the Gods are almost entirely irrelevant.
What should happen instead?
Instead, your dwarf would have his divine order turn their back on him. Pelor may do so, but it's highly unlikely he or his order had much contact with Pelor or his servants to begin with. The dwarf would still have his powers, because D&D 4e doesn't have any concept of power-revocation. He may simply be unable or unwilling to use them, possibly out of shame, or out of threats by his order. How you handle that is up to you.
Is there any reason Pelor shouldn't revoke his powers?
Yes: You'd set a precedent that 4e works the way 3.5e did where it does not and should not, and send two clear messages. First, that divine classes should constrain their actions based on alignment under fear of loss of all power, and second, that alignment is mechanically significant.
Neither of these things are the case otherwise, and D&D 4e is designed based on the idea they aren't the case. Classes are designed to be equal and balanced at all levels, and the alignment system is mechanically so insignificant you could remove it and affect almost nothing. 4e doesn't share 3.5e's philosophy of major catastrophic character damage being an OK thing - destruction of levels, attribute scores or unique equipment generally just doesn't happen, and nor does loss of class features.
Overall, in 4e I would strongly advise staying with D&D 4e's philosophy of Divine classes not being god-fuelled or under threat of losing their powers. The consequences suggested - a character's order hunting them down, among other things - are more appropriate for 4th edition, and push the story forward in accordance with its heroic themes.