no it is not weak at all
one of my builds is melee, despite being a dumbass (intelligence 1) and unlucky bastard (Luck 1, Charisma 1), but with strong arms and tough body (Strength 10, Endurance 10) and all the right skills (unarmed 100, melee 100) right perks and right weapon, etc, he can axe an entire army of NCR rangers without a scratch.
Believe it or not, a melee build at higher level can punch a deathclaw to death with just one hook, barehand, in that case, you are Chuck Norris of Mojave Wasteland