I’m sorry to hear you aren’t enjoying it. My party seem to be having a blast. I think this is one of the difficulties of a player judging a module without understanding how much of it was influenced by the DM.
Playing. 5d6+5 is 22.5 damage on average. That means if you have 11 hp or less, you'll flat out die more than half the time ... and even if you have 12 or 13 hps, a slightly high roll will do it.
I’m not sure if you’re aware but the DM guidance specifically states that the boar targets a hunter guide on its first round, not a PC. The boar is also bleeding heavily so gains a level of exhaustion each round. By my maths there’s about a 1 in four chance of a PC dying in the encounter less if they optimized. But that doesn’t mean the end of character at that point because of the paths. I don’t want to spoil things, but dying in the boar encounter is not player death.
That is not the problem with them - they're badly balanced and mechanically poorly designed. The paladin gets the following spells: Hunter's Mark, Find Familiar, Fly, and Haste. That is a really strong set of spells. Then they get a 60 foot frighten with a set DC of 14 at a low level (3rd). They're evocative (some perhaps too much - The Amazon is a bit too Wonder Woman), but the balance is just off.
I think you’re being a bit harsh. Most of these Paladin spells are already on other Oath’s lists and the example of haste doesn’t come online until 9th level by which point the party almost certainly has far more beneficial stuff. Not to mention that most of these spells are concentration and the Paladin is already tight on spell slots. Sure the fear aura is good but other Oaths also have a fear aura or other similar powers. DC 14 is good at 3rd level but let’s be honest a normal paladins saves at that point are probably going to be DC13 and balance will reduce its effectiveness when they get to higher levels.
It does make me chuckle that the Amazon is too Wonder Woman when WW is directly based on an Amazon and is the representation most modern players are going to be familiar with. This seems like a bit of a low blow. Particularly as they have several abilities that WW doesn’t seem to.
The Epic Quests are laid out, so I do not considerf this too spoilery - they start storylines that players engage in and then the storylines dry up if the PC is not there to complete them. That isn't too bad. However, if the PCs bring in a new PC late in the game, there are story elements that were to have taken place for their epic destiny that may no longer make sense because NPCs that were involved in that storyline are no longer in the same situation. Yes, you can awkwardly modify them, but - awkwardly. And a lot of these Epic Destinies feel like side quests in old MMORPGs - but ones that just happen along the storyline of the main game. You get them because they fall in your lap.
I’ll be honest I don’t understand this part. The epic paths are there to give players compelling reasons to engage with the campaign world. Early on they are part of the main campaign but as campaign expands into its sandbox it gives you reasons to explore. Maybe you haven’t got to this bit yet.
I don’t really understand why if you brought a new NPC in you wouldn’t have simply had the early stage interaction already happen. A character has already met that NPC and got their answer or item and is now looking for the next stage. The paths are actually a really good way of introducing a new character… they join with the party because they are looking for X and the party has the means to get there.
All in all, you are of course entitled to your opinion and I’m sorry you feel the campaign isn’t very good. I can’t help feeling this is because you’re seeing half the picture.