Constructive & Helpful!
With this talk about Shaman's "mana problems", I am honesty surprised that no one has mentioned the fact that you can use 2 buffed Hydrophobias per 1 use of Ancestors Flame. This is statistically the best way to conserve mana and deal as much damage as possible per mana spent since 1 buffed Hydro is 2 Flames worth of damage for only 1.5 times the mana cost. Although when it comes to lower hp enemies, you usually kill with just 2 + 3, so it's not always that relevant, especially at max level using damage boosts, plus there's a lot a lot of times when 1 Flame worth of damage is better to take down the last couple hundred HPs instead of waiting for Hydrophobia to get off cooldown again, in which case not using Hydrophobia twice is actually more efficient. I just shot myself in the foot with that last statement, didn't I?
The only time it's super relevant is if you are both in mana and hp troubles against a boss and needs to heal as much as possible while saving as much mana as possible, since using Hydrophobia in bossing is generally a bad way to spend mana, but if you are already in that situation, chances are you either did something wrong or tried to take on something you shouldn't and in both cases, might not even be able to save it anyways.
It's maybe not something you think about if you are just using it on the side of something else, hence why a lot of people just spam 2323, because it's the simplest way to go about it.
Brain dead classes are the best farming classes.
"It's not about the destination, it's about the journey"
While probably not true for a lot of people, seeing how many people want to avoid doing actual farming to get results, it still holds some significance. Let's say you are going to start farming for an endgame item, BLoD, for example. If all you think about is "how do I get to the goal the fastest" instead of "how do I make the grind for Dust and Essences more interesting", then you are definitely going to run into the problem of AQW getting stale quickly. This is why I recommend having multiple classes for the same purpose in your inventory at the same time, because then you can switch out classes when one gets a little too boring to constantly use without the efficiency. It's not going to be 1 to 1 comparison between classes all the time, using LC to kill a high hp boss will always be faster than using LDK and using a class like RBM in Boxes instead of BB, Shaman or Vamp Lord will increase the time spent doing the same task, over a longer period of time. I do have my favorite class for AoE mass murdering, but I do always try to mix it up once I feel like the class either isn't cutting it anymore, maybe want to use a less attention needing class or maybe a more efficient class to finish off the farming session quickly. Unless I specifically time how long it takes for me to obtain X resources with X class, I can hardly tell the efficiency difference between different AoE classes while farming, in a lot of cases.
Is AQW necessarily interesting and engaging through every grind? No, not by a long shot, at some point, even the most dedicated players will give up and just start doing lazy farming while doing something else on the side, no grind can truly hold anyone's attention for a sustained amount of time, especially if that grind involves killing the same 1 or 2 enemies for tens, maybe hundreds of hours, which is usually the case for these endgame/hardcore grinds.