I think 5 is too many and am not sure that Martial needs a change.
Martial already gets "two combat talents" and "two martial techniques" as advancement options.
Based on all the characters I've made (well over a dozen for myself plus over half a dozen for other people), I think the archetypes are (at least for the way I build characters):
- Expert - by far the most versatile archetype (but you do generally give up one rank in combat or arcanum skills vs another archetype)
- Martial - Advanced Armor Training is huge and two different advancement options giving two combat-related talents is nice as well
- Arcane - I only use Arcane if I want an Elder or Eldritch caster or, more rarely, a full Psionic caster from creation
- Divine - I have never built a Divine archetype character that I didn't like better as an Expert
At most, I would change the Martial advancement option from two martial techniques to three.