You have to take into consideration all scaling and all attributes.
In the case for heal, it also scales off of max HP so if you build CON on your monk, you heal will do more.
For Deprotected Zone there is an attribute to decrease defense of the enemy effected when they are hit with a sword attack. This can be extremely useful in groups with swordsmen and also a generally good skill as a monk is mostly physical.
Regardless if you can scale with it or not, ask yourself, what else are you going to put your points into? If you leave heal at level 1, then deprotected zone will end up being level 4 regardless due to your extra points.