Best Class = Coolest Looking Class
Seriously though, something I personally have found is that given that a majority of your questing is going to be low stakes fights, with the amount of times you'll be seeing each spell's animation it's way more important for your enjoyment in the long run that you click with the school's visual identity! Clicking with the gameplay is also important, but the meta isn't really something to be concerned about unless that efficiency is something you deeply enjoy. My personal idea of (other people may differ) a basic school rundown is:
Death - Arguably the most efficient, but takes a while to truly kick in given a lack of 4 pip aoe (unless you manage to obtain Ship of Fools or Deer Knight). Death has lifesteal, antiheal, and can effectively deal damage OR support. If you get silly with it you could probably even manage to tank through drain-tanking, though that might conflict with some setup. Some themes are icons of death, souls, the undead, or spooky halloween-esque stuff, with a touch of the earth, likely as a "return to nature when you die" type deal. Some representative colors would be tones between black and white, dark browns/greens, and ethereal light blues.
Storm - The second most, or most efficient school depending on who you ask. Gameplay is that of a glass cannon, with incredibly strong attacks but the ability to die if somebody looks at you wrong. Where death can tune out for most fights and end up full health, allowing for an incredibly easy experience even when solo, storm can be more of a coin flip, needing to strike fast and take enemies down before they get the chance to hurt you. Storm can be easy for some, but you need to be a bit more mindful of your setups and strategies than you would on something like death if you want to survive. Storm loves getting buffed, whether by itself or allies. Some thematic elements of the school would be lightning, rain, and quite a bit of the ocean, whether it be stormy seas or what lies at the ocean's depths. Some representative colors would be dark/deep sea blues, purples, yellows, and the occasional white/blue for lightning.
Fire - The OTHER damage school. Fire hits hard, but has a bit more survivability than storm. Where storm likes to strike fast, just like a lightning bolt would, a lot of fire lies in damage over time, slowly burning your enemies and easily going through shields, unlike storm who loses a lot of damage when hitting shields due to its reliance on quick hits. Eventually you'll be able to obtain spells with detonate effects, letting you blow up damage over times for an instant amount of their damage, adding a new element to your strategies should you choose to use them. Some of fire's thematic elements would be fire, lava/magma, and general heat. Some representative colors would be red, yellow/gold, and ash black.
Myth - Myth, statwise, is akin to the bruiser archetype, something like a warrior, with damage and survivability both being somewhere in the middle. While most people talk about myth's identity in the minions, where you summon legends to aid you in battle, my myth playthrough has shown me that another key part of myth's identity is the utility it can provide. I like to relate abilities to the school's theme, and myth is almost able to nullify your story, your acheivements, your past 4 turns of setup, on a whim, as myth has quite a few spells focused on removing traps, shields, or blades. Some representative themes of myth would be greek/roman mythology, marble, and it's a strange thing to notice but a lot of movements and attacks feel fluid and curved. Some representative colors would be bright sea blue, yellow, and ivory white.
Life - Life and ice are, to me, around the same level of efficiency. If I had to choose, I would give life the edge in solo due to the ability to heal itself, with a bonus in how a good kookaburra pet can drastically improve your experience. Where death is the endpoint of life, and steals it away, life is the giver of life, focusing on healing and support. Regardless of the actual damage you do, even if it's more than everyone else on your team, you will almost exclusively be healing in a group setting. When soloing, life's able to repeatedly use low to moderate damage while healing itself if it so chooses. The survivability is high, with the tradeoff of lower damage. Some thematic elements would be meadows, forests, jungles, and their caretakers (i.e. fairies), with everything revolving around the theme of nature. Some representative colors would be green, brown, and white, with the opportunity for the whole rainbow to make an appearance.
Ice - Ice is slow, but unstoppable. It has low damage for the tradeoff of the best survivability. While it lacks the heals of life, its shields and raw stats make it difficult to ever eliminate. Battles with ice will be slow moving and filled with intent as the freezing cold slowly whittles down opponents unable to break through your wall. Some thematic elements would be snow, ice, and the cold. Some representative colors would be light blue and white.
Balance - Balance is the strangest of the schools, meant to both make use of and complement all of the other 6 schools. Balance's efficiency is all over the place, changing from player to player, fight to fight, and depending wildly on who you ask. You can do everything, but unlike death you aren't great at every role, and put a bit more weight on support. Balance's variety of utilities can give them the role of strategist, helping dictate and plan the flow of battle. Some examples of balance's themes are the sand, its inhabitants, and blends of themes from other schools, with an emphasis on trios (storm, fire, and ice are the elemental trio, and myth, life, and death are the spiritual trio). Some representative colors are sand beige, orange, brown, and the representative colors of the other schools.
Hope this helps! Schools were listed in order of how efficient at solo PvE I believe they are (closest thing we've got to meta), and I tried to dive into the school's identity in both gameplay and visuals. You'll likely have more fun prioritizing what you like over the meta, especially in an unconventional game like this, but I know being efficient is how some people enjoy games, and that's just as valid a way to interact with them.
