It has awful defences because that's how Gamefreak designed Lucario. Besides, its steel typing means it's resistant to 9 moves & immune to toxic, so it's meant to a fast sweeper that can take resisted damage rather than a tank.
If you want a bulky Fighting Type, there's Hitmontop
Ability: Intimidate/ Technician
Item: leftovers
EVs: 252 Sp. Def, 128 HP, 128 Atk
Nature: Adamant
~ Bulk Up/ Fake Out
~ Mach Punch
~ Stone Edge
~ Bullet Punch
Standard set for Hitmontop; bulky, and if you want you can put Rapid Spin on it too.
OR
Item: Choice Band
EVs: 252 Atk, 252 Speed, 4 HP
~ Close Combat
~ Mach Punch
~ Bullet Punch
~ Pursuit/ Stone Edge
This isn't a common set for Hitmontop; most people go for a Bulk Up set because they want a Rapid Spinner, but I'm going on the same principle as Technician Choice Band Scizor (who has a slower speed than Hitmontop anyway).
And Scarfty
Ability: Shed Skin
Item: Leftovers/ Chesto Berry
Nature: Adamant/ Careful
EVs: 252 Sp. Def, 128 HP, 128 Atk
~ Bulk Up
~ Crunch
~ Drain Punch
~ Rest
This is my favourite Scrafty set; forget Moxie, it's not fast enough for that. Also, one Will-O-Wisp and its sweeping set is finished. With a few Bulk Ups, it will be able to take x2 weakness hits with ease, and Rest + Shed Skin is there to replenish health and continue sweeping.
