Smithing alone makes weapons pretty overpowered, even without the use of alchemy/enchanting to help boost it.
I wouldn't sat they are overpowered by Smithing alone. Here is a simple test I conducted a few weeks ago.
With level 1 Nord, swords, (Steel, Dwarven, Glass and Daedric) their base damage is 9,11,13,15.
Level 17 - 1H at 100, no perks and no Smithing, the base damage is 12,15,18,21.
Level 17 - 1H at 20, Legendary status is 27,30,33,36.
Level 17 - 1H at 100, 5/5 Bladesman and no Smithing, the base damage is 24,30,36,42.
Level 25 - 1H at 100, 5/5 Bladesman, the base damage at Legendary is 54,60,66,72.
That seems pretty reasonable to me. Where people get the overpowered mess from, is when you continue to upgrade the gear PAST Legendary.
Ok the curiosity got the best of me. Here is the numbers for 2H. Same test...
Base damage for a level 1 Nord (Steel, Dwarven, Glass, Daedric) Greatsword 19,21,24,27
Level 17 - 2H at 25 w/ Legendary ststus 30,33,35,38
Level 17 - 2H at 100, no perks, no Smithing 26,29,32,36
Level 17 - 2H at 100 5/5 Barbarian, no Smithing 51,57,63,72
Level 25 - 2H at 100 5/5 Barbarian, Legendary status 81,87,93,102