I thanked God for roles in the Fourth Edition. It made explicit the needs of the party.
I am playing Pathfinder now and our party cleric has decided to change his channeling into negative damage energy and to concentrate his spells on commanding undead. So now we have no buffs and few heals. And his evil ways mean I feel unable to play a Paladin or Good Cleric. Because he is "creating a character out of an image in his head" rather than worrying about what is necessary. (I wish we could just leave him at the dungeon entrance. Heh.) At least a Fourth Edition leader can always heal at range with a minor action a couple of times per encounter regardless of his feats and powers.
You illustrate one of my favorite things about d20/3.x./PF. It is awesome that you can make a Palpatine cleric, a healing cleric, a fighting focused cleric, a master of the undead type. Or a little of all of it. With the additions of domains and subdomains into pathfinder they have ensured that you can deviate away from "healbot" as a character theme and play the cleric in meaningful ways. The Palpatine cleric you describe is actually super effective at most levels. Several selectively AoE attacks a day with the same damage as sneak attack? yes please. Undead pawns to control movement on the battlefield (That also as a side effect get healed by previously mentioned AoE)? Yes please. Add in the clerics buff spells and pretty good melee options and you have a very formidable and useful toon.
Now of course the rules support "healbots" as a play choice as well. One of my roommates who just started playing PF the other day while making a cleric to play said they wanted to make the "healing monster" And he made an awesome one and has had a blast playing the toon. I think its awesome that many types of play can come from the same class. If you lock the classes mechanically into a role what you are really doing is making the roles the class. Sure you could have a primal defender, a martial defender, and a blueberry defender, but by making the role a mechanical implementation it doesn't really matter what you call it, it still washes out the same. This sameness is one of the things that made 4e less enjoyable to me. In addition to all of the powers kind of feeling the same to me , a lot of the classes did as well. And it made me like the game less.
I think the problem you illustrate in your post has nothing to do with an argument for or against roles. It has to do with your party not talking with one another and making sure you had concepts that fit well with one another. Obviously you have an alignment issue. Usually in most games I play in or run alignment is always a topic that is discussed at the start of the game and with the addition of a new player. My usual way of handling it get a majority vote from the players on wether they want to be good guys or bad guys. Once the paradigm of alignment had been stated I alert the players that they can make a toon of any alignment they wish but outliers must find a way to hide in the paradigm or make it workable.
The cleric you presented is obviously evil, of course you can no longer make a paladin or cleric that is good aligned and travel with this fellow. But you could make a neutral cleric and still have great healing and do it. There are also druids, witches, oracles, alchemists, rangers, bards, and inquisitors that also have access to healing spells.
The thing is PF is a group experience. If this was a new player your party should have alerted him/her of what your group of toons was really good at and what they needed help with. If this was a player that was with the group from the start he/she should be allowed top make the character "from an image in their head" The idea that one player is responsible for buffing/healing based on class choice is silly. Why should the player of this cleric have to sacrifice playing the toon in their head, so you can be buffed healed and get to play the toon in your head? Group cohesion and getting all the bases covered has more to do with players being able to talk with one another than it does packaging forced concepts into classes to get them to fit into a role. My groups discuss not just class but also concepts at the start of character creation. So if one of my parties fails to have someone heal or stand up from and get beat. Then its a group problem not a problem of a particular player.
The only area of RP games that I could see any benefit for roles is in organized play where you don't necessarily get to enjoy all the benefits and social contracts of a group that meets regularly. But I have found that the alignment issues you mention work themselves out. I have to step in every now and again if folks get poutyfaced. But in general if an outwardly evil toon tries to roll with a posse of all good toons its a short love affair at best. But I don't try and prevent it from a game standpoint, because sometimes the interactions from these toons with drastically different views is very good and fun to play through. I only put on the referee hat if it looks like folks aren't having fun as a result. But if the group is having fun with it then I let it go and even nurture it.
On the idea of parties going out with a glaring weakness like "very few buffs and heals". This a party weakness, not a player problem. While in the groups I run I don't usually force anyone into roles. If they are glaringly missing something I might mention that they have no melee fighter or no one who could even cast a healing spell. Sometimes they are like "dang we forgot about that" and someone changes concept, sometimes they roll on without the missing component. Once they start adventuring in earnest one of two things usually happens:
1. The party suffers a defeat/partial defeat/lack of success that sees one or more toons dead or retired and new toons joining the group shoring up the weaknesses.
2. They party attacks the game with a handicap and has a great time because of it and gets some level of success from their adventure and keeps at it missing role be damned.
It doesn't sound to me like your group really needs roles to succeed. If I had a player come to me after the game was started and say "Malk, I come from a 4e environment where choosing to play a cleric has mechanical assumption of healing so I assumed the cleric would fulfill that role. When I made my toon I thought we had a healer, I can see we do not. I do not feel good about our group going into a dark hole with poor healing. I would like to retire my toon and roll up something with better healing capabilities for our group. IS that cool?"
I would totally let them swap out. I think most DMs would let this go down. I would also let the group go into the hole with no cleric, to be chewed up by the encounters or to perhaps succeed against stacked odds and coming out feeling like a baddass.
The removal of mechanical roles is a good thing. It allows people to play more different things with smaller amounts of splat required. The issue you painted doesn't have anything to do with roles other than perhaps an assumption on your part. You need to talk to your party to find out if there is a want for a healer. Let Palpatine be, if your group can't survive without a dedicated healer, the dice will sort it out for you. Or you can take one for the team and roll the healer yourself.
love,
malkav