There is something about Tinker guild may be removed and every one could learn crafting skills to make items himself...

Well, as an option I would suggest some changes to Tinker guild:

1. Skill Specialization.

Armourer skills:
leathercraft, FA, runes (probably corpse skinning)
could use reinforce armour with blacksmith (self only)

Weaponsmith skills:
carpentry, FW, runes (probably lumberjack)
could train balance weapon or use it with BS (self only)

Other skills are common.

Specialization affects skill cost and caps.
So, if you are not specialized you get cost at the middle, and caps like 120%.
Specialization in armour lowers cost for armour skills, and increases cost for weaponer skills.
Also, it manages caps going to 150% and 100% accordingly.

2. Spec XP.

I like if tinkers could get same XP for all main skills:
FA, FW, runes, carpentry, leathercraft

But let them train it to max CAP only at certain spec level - 30, for example.
So, armourer-tinker with spec level 20 could train each rune/FA/leathercraft only to 100% maximum (150/30*20). Thus he could get less XP than when he hit level 30 and train something to 150%.

3. Combat

I guess, combat is well balanced for tinkers. They work hard and test weapons and armour they made. So, they supposed to be good fighters as well.

Best Regards,
-Guinness.