Really, if you consider that I'll run 1-2 characters for a 1-3 year campaign, I'll get to experience very few subclasses. So I'd prefer for them to explore something big and unique that changes the play, not a collection os math changes that at the end of the day just modify a die roll a bit without giving new, flavorful options.
So my advice is go big or go feat.
Go Big: Remove every little bit of math trick and make them flavorful and unique so that a Fighter (Dwarf) doesn't play like any other fighter or barbarian, including Fighter (Elf), etc.
Go Feat: Generalize core concepts of these and make them into feats for anyone of that race who wants to be "more so".
High Dwarf
You are a paragon of your race with strong bloodlines.
- +1 CON
- Increase your CON maximum by 2.
- Add your proficiency to any checks or saves to move, grapple, restrain, hinder or prone you, regardless of what else they do. If you already add your proficiency you may add it again.
- Add 2 to AC vs. creatures that are Huge or larger.
- Add your CON to any Charisma checks targeting dwarves.
(Yeah, I wandered off what you had in Dwarven Shield, just playing around. I didn't do Dwarven Weapon Training because that's of limited applicability; some characters might not use weapons and for a feat it was already pretty close to "too powerful".)