Sure, and certainly you can specialize yourself into a corner. Fair enough. But, I mean, a warhammer? Doesn't seem like too specialized. Of course, 5e doesn't let you dive down the niche hole quite as deep as other versions of D&D. Yes, I wanted a warhammer, and that was my choice, but, my character didn't suffer any negatives for not using a warhammer.
At worst, you might be out a feat - something like Great Weapon Fighting or Sharpshooter - but, other than that, you can't actually specialize too much in 5e. So, mechanically, it doesn't really matter if you use random tables or not.
But, it does feel ... off to have a character concept get flushed down the toilet simply because we found a better widget.
Funnily enough, in the next campaign - Ravenloft - I played a bow focused ranger. Not a single magic bow or arrow to be found in the whole bloody module and we practically stripmined that thing. Then, I played a cleric in Storm Kings Thunder. Not a single mace or warhammer to be found. Three straight campaigns without a single magic weapon.
It is nice that 5e doesn't really need magic weapons.