One of the unfortunate bummers about Avowed—which is set in the Pillars of Eternity universe—is that you'll be limited to playing either a human or an elf for story reasons, as your adventurer will be an envoy from the largely elf-slash-human dominated Aedyr Empire. That's kinda disappointing, seeing as Aumaua, Dwarves, and the fuzzy li'l Orlan are all appealing character choices from the setting.
Narrative aside, it seems like the main reason behind the choice was motivated by the technical nightmares of a first person camera. That's according to game director Carrie Patel, who spoke with IGN recently on the subject.
"We want to make sure that whatever experience we're offering is smooth and natural … one of the things [that's] easier to account for in an isometric game is just the variation in sizes." While she notes that Aumaua are "roughly on the same scale", Orlan and Dwarves present a whole party's worth of challenges.
"For each of those, especially in first person, you're adjusting the height of the player character's capsule and sort of where their weapons are relative to enemies and how their hits land," Patel says. While I do see her point, there've been first-person RPGs with a big variance in player size before.
However, Avowed is notably aiming for heavy, Vermintide-inspired brawling with some physics-based shenanigans thrown in. While something like The Elder Scrolls 4: Oblivion had pretty variable sizes based on race, I don't think anyone would describe that game's combat as "weighty."
For Patel and the team at Obsidian, it's mostly a question of where they want to put their resources. "it's obviously not that any of these things are impossible to solve, but you're always making choices and choosing your priorities in development." Avowed is scheduled to release in fall 2024, as per an extended showcase during the Microsoft developer direct last month.