I'm casting
Restoration and
Lesser Restoration to cure them up just like the cleric would...
While certainly true that the Paladin has access to these spells, the earliest he will access Lesser Restoration is L4 (L3 for the cleric so no biggie) and he'll be L13 before he sees Restoration (versus Cleric L7). He's also gaining the spell slots at a lower pace.
Of course, you can always buy wands. 21,000 gp for Restoration doesn't compare well to 750 for CLW, but you also have the other Paladin advantages. Having a Paladin rather than a Cleric means you spend more to have Restoration access, but the paladin adds melee power, especially against evil creatures (like, say, level draining undead).
To the bigger question, I think D&D, and Pathfinder by extension, are games of teamwork, and there is an expectation of an array of abilities. I think doing without a cleric is probably more viable in Pathfinder, and certainly no less.
If you're missing some core abilities, it will certainly change things. However, I don't see writing AP's on the expectation there will be no arcane casters, or no warrior types, will create issues for far more groups than assuming those bases will be covered in some manner. I don't think I've ever used a module without reading through it and assessing which challenges are rendered underpowered due to group composition, and which might need some modification to avoid being overpowered.
In this specific example, I think a pretty wide array of viable options have been suggested. I also think the ability of the party to back out and plan greatly enhances their power - you aren't stuck with what the casters selected for today, nor the weaponry the warriors typically use, so you can come back tomorrow - and the next day, if need be - with a group better customized to address this specific threat.
Any martial character can pick up a Great Sword, have their damage capacity augmented with buff spells we typically ignore because melee damage isn't the team's typical forte, be aided by other team members whose usual combat role is different, etc. Not every challenge is, or should be, a perfect fit with the party's areas of greatest focus.