Yeah, I started out doing the same thing with wheat. Different people will have different thoughts on the matter but I think most would agree that you can still get good head retention without the wheat. Wheat can help with head retention and maybe it's the easiest way for you to do that. Just be aware that it also introduces other factors into the equation like higher protein content, more variability across wheat varieties, potential challenges to milling, etc. The higher protein can potentially cause chill haze, for example. Tinker with it and see what works for you. I like wheat, and I use it often, but other factors can come into play when you use it.
That's great! It sounds like you're well ahead of things. Again, if the beer turned out great then maybe you don't have to change much. Chlorophenols weren't a problem for me for several brews. Maybe it was just a spike of chlorine in my water source but now I use campden each time to be safe. For other recipe changes...I would only make changes if you want to make changes. I tweak to see if I can improve something. When I really, really like a recipe I save it and brew it the same way. The more you learn the more variables you'll have at your disposal to change. I'm just glad you're enjoying!
Learning to taste is part of the journey. One way is to get a couple different versions of a similar style. See if you can find out the hops/yeast they use and start trying to pick out differences. Try your beer and start looking for flavors that relate to each component. For the hersbrucker I typically get some spicy, grassy, and definitely some fruity notes. The malt will contribute cracker, bread, etc. You might get some fruitiness or maybe light sulfur (think faint burnt match) from the yeast but you might not. Specific to the novalager yeast you might have some apple flavors or other low notes of fruit. The big question to ask is what's prominent in the beer, though? Is it mostly crackery, spicy, etc? If you're tasting predominantly bready and noble spice then maybe the yeast isn't contributing too much, for example.