Plants grow fine with just water.
Ferts just make them grow way bigger and branchier.
If you grow a plant with just water its going to be real stringy and wispy.
Jumping into full concentration nutes right when you start fert is never a good idea, you always step it up in slow increments to find what the plants nutrient tolerance level is.
I am in quite a predicament right now, I have one plant that can take ec 1.9 of nutes and the other one can only take about 1.2 in the same container, needless to say the 1.2 ec plant is a runt.
How perfect the plants start out is in no way indicative of the final product, example, nute burned plants that end up being champion oz+ plants, or clones that start out real nice and healthy that someone fucks up and neglects. Both of these can make a full recovery, as long as problems are addressed in VEG the plant should have no problems in flowering. If you get made nute burn late into flowering you are fucked, thats why its good to get the hiccups out of your systems in veg.
Healthy plant at the end of veg = healthy plant in flower.