-quests
-items
-recipes
-Solutions
-abilities
-events
Like I said, you're nitpicking
Death of a thousand cuts.
There is nothing that fundamentally hurts custom origins on their own. It is a bunch of little things that makes the game favor origin characters over custom origin characters.
Custom characters are of tertiary importance.
What are even your solutions to these "problems", you seemed to have ignored that conveniently?
-4 selectable origins
-Custom Origin quest line and events unique to them.
Yeah that is about it. As I said treat them like the 7th character.
This would fix all the problems of making the custom origin character a secondary character of their own story.
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By the by, what character you playing? Likely custom origin.
Fane doesn't start playable with the Mask of the Shapeshifter, which also isn't necessary.
Nobody but, like, Sebille start with any custom items, in fact, and her custom item is her needle which does nothing mechanically but lets her do story stuff.
From my poking around in the EA, not a single character starts off with special recipes.
Solutions? Like what? For quests? Oh yeah, because you can't choose like twelve ways per quest per character regardless of what character (Including custom) you're playing. The number listed is an exaggeration, maybe, but the number of solutions doesn't really change.
Abilities... Well, no sher, shitlock. Race and origin determine like maybe 3 skills. Yeah, origin characters get the same skill, but it's not like that skill is BAD. What amounts to an invulnerability bubble is actually damn useful.
Events... Well, I'll give you that, on the condition that you planned to play the game without companions. With companions, you get not only custom events, but to see them play out and intervene in them both, because you choose to attack or defend or talk them down or so many other things.
I can't think of a single thing that custom characters really 'lose out on', and then there's that entire game mode, y'know, Game Master Mode, where if you like roleplaying you can do with your friends and you'll all be best off being custom characters and telling and weaving new stories that the origin characters wouldn't fit into.
And even -then-, even if you ONLY want the singleplayer main campaign, you're still getting the same basic story. You'll still get bless the same way as the origin characters, and other special source skills. You'll still, assuming it's still in, be able to earn new tags based on your playstyle. You'll still be able to romance the romancable characters, and kill the ones you don't like, and craft the items you know of, and...
And you won't be FORCED to be a possessed bard, or a psychopathic murdering elf who licks strangers, or a pompous arrogant self-inflating demon-dealing lizard more red than blood. You can be YOU, with your backstory. No, you can't be certain things like the former ruler of an empire, because those already exist in the lore of the world, but you could've been an adventurer, or a merchant, or whatever.
Your most valid complaint is the craftingt hing which Fane -might- start with the ability to craft the mask of the shapeshifter as a recipe. But just -talking- to him in fort joy seems to be enough to get the recipe for the face-ripper and the masks, so even if you want to do a 100% solo campaign as a unique undead lizard hydrosophist-summoner, and feel you absolutely MUST use the Mask of the Shapeshifter, then you by all rights -can-. I honestly don't think Larian would prevent that just because they also put the work into the origin characters.
Essentially, by all rights, your custom character IS the seventh origin, because you can make them do things that would actually be BARRED to the other six. There's at least one guy in Fort Joy who even up and refuses to talk to the Red Prince, and that guy sells sick gear. There's another character that if you're playing as Lohse you -have- to try and kill. You actually GET THINGS for being custom, because you don't get things FORCED on you.