Building Custom Races

I’m working on building some custom races based on products from older D&D supplements (things like Rakasta, Phanaton, etc.) and I noticed that in all the discussion of custom race design, one thing which seems to be consistently ignored in calculating a racial cost is the ability of Elves to cast arcane spells while wearing armor. I believe Zaharans have this ability as well but when I looked at the playtest thread where the Custom Race design rules are discussed, this ability seems to be ignored.

This is a huge advantage over “human” characters and one I’d like to understand how to model in a balanced way as I design some of my own custom races.

Thoughts?

I was under the impression that a class that had both arcane and fighting value could cast while wearing whatever armors it is proficient with, rather than it being a special demihuman thing.

That’s the way I’m running it, although of the official classes the only class that it matters for is the Venturer.

That’s correct. It just seems like a special demihuman thing because of the class builds.