If you don't have anyone on hand to pick a lock, you pass by the door, maybe beat it down, maybe cast a spell like knock, maybe beat up some guards and take their keys. There's more than one way to get through a locked door.
If you don't have anyone on hand to remove your curse...historically, in D&D, that has meant that you're just cursed and it sucks to be you. But if there's multiple ways to deal with curses -- kill the critter that gave it to you? Make a few saving throws? Fullfill some requirement of it?
I rather like the idea of some sort of rules-supported alternative to remove curse that can be implemented, and was always a bit disappointed with the various versions of DnD I played that never spelled out some sort of alternative that could be used. What ever happened to the time honored Quest to find the rare herb/mystic dingus/heroic task that would break the curse? Although it was fun as a DM and/or player to be creative to find workarounds, it really shouldn't have always been needed. I don't really pull many punches in the games I run, because I know my group is pretty creative and can usually figure out some sort of bypass, but the one time this was tested pretty harshly was when I decided to run them through Heart of Nightfang Spire. Without a cleric. Two weeks' travel from the nearest town. It took them months of real time before they were able to come up with the party funds to invest in crafting a rod of negative energy protection or some such so they could actually make any progress through all the energy draining creatures. I probably should have given them a dingus much earlier, but I really got to like the "To the North lies a place called Nightfang Spire" jokes that started.
As to why they had no cleric? None of the experienced players were interested in a cleric for this particular game, and after some pretty disastrous attempts to let new players play what they liked in 3.x, I started recommending that new players specifically avoid clerics and druids. When you have to remind someone that you add skill ranks and your stat modifier to your skill roll more than half the time, letting them fiddle with such a large pool of spells can literally take hours away from the group, and even more experienced players can sometimes fall victim to the glut of spells available, especially once splat books are taken into account. It's the same reason people take forever ordering dinner at fast food restaurants. Even when McDonald's is running a lot of promotional menu items, it's not like the guy who always gets a Big Mac is going to suddenly decide he wants some strange fajita wrap of some kind, but he's going to spend three minutes staring at the menu before he orders his Big Mac because all the choices paralyzed him. As much as people talk about having more options is great, studies have proven that the more choices we have, the longer it takes to make a decision, and when everything is new, having 40ish spells to pick through every game day can be daunting. In theory, a daily spell list doesn't change much. In my experience, new players who pick a list tend to change it often, dropping spells they didn't use for new ones they might.
I remember spheres from back in the 2e days, and I did enjoy them to a certain extent. One of my favorite characters was a dwarven Sunite priest with a 5 intelligence and gold-etched full plate. The down side to spheres, at least as some people here are proposing them, is the fundamental exclusion of any new materials. That's great if you only ever want to run a core-only game. Unfortunately, if spheres are some sort of never changing beast, and new spells are only added via new spheres, unless there's some sort of method to gain access to more spheres in the future, existing characters can never have those new spells. Even if DM's rule that new spells can be added to those existing spheres, it takes a lot of bookkeeping to check each supplement as it comes out, label each spell you wish to include with a sphere, and provide a list for your players of what new spells are available to their sphere. A more meaningful method to implement a sphere like system was mentioned earlier, if WotC used some sort of keyword on each spell as a method of grouping them thematically. That way, new spells could be incorporated into existing spheres fairly easily.
Alternatively, even sticking with divine casters automatically knowing all core spells, including some support for divine spells that aren't automatically known would be a nice solution to splat books. Those new spells could be long lost spells/prayers recently uncovered, spells from remote monasteries, etc. That would at least make it easy to incorporate new spells if desired without making it onerous to do so. This would not be my ideal, to be honest, I've always felt that every divine caster shouldn't just automatically know every spell. Paraphrasing a book probably explains how I feel about divine magic best: "Why do I have to memorize all these rituals and prayers, you're my god, can't I just ask you?" "I'm busy, if I had to spend the time to listen to every priest, I'd be here all day. Those rituals and prayers let me just subconsciously grant my powers to you". Just because a god could listen to and grant each request for magical aid personally, it would seem pretty tiresome to me to have a constant stream of whiners asking for mojo 24/7 when they're trying to do all sorts of godly deeds.
I personally favor some kind of known spell system, but a nod could be made to allow access to spells you don't know by direct plea. IE - you don't know the spell/prayer/ritual to cure blindness, but the evil lich just blinded the only guy holding back the golem servants from smashing you and your friends to pieces, so you cry a desperate plea to your god etc. Whether this fell into some sort of 'divine intervention' rule set or was codified into a specific class ability (once per day spend a full round to petition your deity to grant you any divine spell off of your list, or some such) could be hammered out in the details. I used a similar principle in my 3.x games, where any divine caster could petition their deity for any spell, regardless of level, and have a chance of getting it granted. I also warned them that channeling that much power when they weren't ready for it could have disastrous consequences on their mortal body. I think I've only seen that house rule used twice, and both times were pretty epic (which is what that rule was designed for).
