Note that this only applies to leveling, not epic/high end items. It's just my observations, I'm sorry if I offend anyone.

1-300: Inefficient, poor quality items vs. mats needed, narrow catalog.

I propose these things... * indicates that it could apply to tailoring, leatherworking and smithing.

a. All items be updated to Cataclysm standards- that includes appearance.*
b. Armor sets for each step on the road to 58, designed to facilitate low level tanking, healing and DPS.*
c. The necessary mats be reduced where needed. *
d. Reintegrate the weaponsmithing and armorsmithing recipes as improved BoE items.
e. More diversity. For the low end, add shields, caster 1Hs, etc.. Stuff that we finally started to get in Wrath and got very useful versions of in Cata.

300-375: General lack of useful items vs. quest rewards, fel iron is annoying, only a few easy skill-ups.

a. Move Fel Iron Chain to leatherworking and split it into caster and agility sets... I'm puzzled why we have this one.
b. Make a tank and a DPS version of the Fel Iron Plate set.
c. More adamantite stuff. I got sick of wading for fel iron.
d. Make the weapons more useful- for example, the Fel Iron Hatchet should be a 2.6 DPS axe with the correct stats, and a mace/sword equivalent for humans should be added.

375-450: Better, but one thing would be nice...

a. Add strength 1H weapons. Not everyone is going to want to use 2H or titan's grip now that 1H is viable again, so there should be an option for those folks.

450-525: FOLDED. FREAKING. OBSIDIUM. Whoever thought of this abomination needs to be tossed in a pen of rabid, fire-breathing camels. It should not take four ore to make one usable unit. Other than that, I love Cata smithing.

Anyone else got something to add?