I love reach - finally an advantage to being bigger than everybody else that was lacking in 1E and 2E. There should be consequences if you try to rush up & attack a 12 foot tall giant - and, that is, the giant gets a poke at you before you can get in your blow.
It's no different than a formation of pikemen wielding 18 foot long pikes going up against a formation of swordsmen wielding 3 foot long broadswords. The pikemen are going to be able to attack the swordsmen from 15-18 feet away before the swordsmen can get even close to the pikemen. And, if there are several ranks of pikemen, they will get in 3-4 attacks before the swordsmen can close. Just consider the 12 foot tall giant with a club to be like the pikeman wielding an 18 foot long pike.
Similarly, in boxing in real life, it is considered an advantage to have longer reach than your opponent, even if it is just a few inches longer. You can jab your opponent from the edge of your reach while he still cannot reach you.