A RDA/RBA makes a world of difference in flavor. I remember the first time I tried a juice I had been vaping for a while in a tank in a dripper.. It was a real eye-opening experience.
That said, I was a bit of a cigarette snob, I tried a lot of cigarettes and got good at pulling out specific notes in the tobacco. As a result, going into vaping, I am sort of able to do a similar thing. There's sort of a "routine" to properly tasting tobacco, and if you follow the same regiment with e-liquid you can replicate that sort of process.
First, take a whiff of the juice (or tobacco). Get familiar with the aroma, put it as close to your nose as you can and imagine what it's gonna taste like. Your olfactory sense is the most powerful sense you have.
Next, take some dry-puffs. Fill your tank or drip on your RDA and puff on it without hitting your fire button. It'll give you a good idea of what flavor you're in for. With a good tobacco sometimes the dry puff would be far more enticing than the actual smoke.
Now take a regular old puff, as you normally would. On the inhale, pay attention to the throat hit. Pay attention to the notes it leaves on your tongue on the way down. On the exhale, do the notes change? Lick your lips, what kind of flavors are you reminded of?
Now take another drag, only this time hold the vapor (or smoke) in your mouth, don't inhale! Roll the vapor/smoke around in your mouth, use it kind of like mouthwash, holding it in your mouth for 5-10 seconds as you swish it around before exhaling. Do you notice any new flavors? Is the sweetness any more or less than it was when you just exhaled? Any new notes or subtle nuances that you missed before?
Now take a third drag, inhale it, and then exhale the entire puff through your nose. Notice any changes in the flavor now that you're exhaling through your nose? Maybe the menthol is more menthol-y, or the strawberry more (or less) strawberry-y.
Not guaranteeing you'll notice differences in all your juices by analyzing them, but it's worth giving it a shot. I've noticed some juices taste WAY better exhaled through the nose than through the mouth. Some flavors taste stronger when you hold them in longer, others taste weaker. Some juices have a different aroma when you exhale without inhaling into your lungs, other juices stay the same.
Analyzing e-juice definitely isn't hype or smoke/mirrors, there are some juices out there with a lot of subtle complexities (many times, I assume, are an accident). Like a bottle of Nana Cream (by Bombies), if you really analyze it, tastes a bit like Juicy Fruit. If you're paying attention, you'll find the nuances.