This post is mostly about my character that I am currently running in Storm King's Thunder, and how I have him play. The hope is to inspire others with how I flavor so many aspects of my character, and how my self-imposed limitation made him probably my favourite character to play thus far.
My character is Galindan, a Firbolg Shepard Druid that was born and raised in the High Forest. The backstory is long but the skinny is that the Grandfather Tree has instilled thousands of spirits belonging to animals inside my druid (Why he's a Circle of the Shepard) , and sent him to fix the ordning because it being shattered threatens a natural balance, yada yada.
So, what's the limitation? Besides druid spells that I feel are baseline or iconic, he can only use spells belonging to the Conjuration school. The reasoning is because he draws the spirits from within to actually cast these spells.
Flaming Sphere? Simply humming bird spirits enveloped in fire that bash into enemies.
Call Lightning? Bees that group in the sky and then rapidly strike downward.
Healing Spirit? A large graceful swan that has flowers bloom below it, causing calm and rejuvenation to those around it.
Conjure Animals? Well ya know.
Entangle? Ivy'd up snakes that appear and constrict
Watery Sphere? A massive blue frog that attempts to swallow the foe
Tidal Wave? Remember that part in LOTR where Arwen just throws water horses at Nazgul?
Heck ya, some cool reflavouring! Though limited to these spells plus the aforementioned "iconic" druid spells, I've also created a backdoor for myself to different spells. Purely through running the adventure of Storm King's Thunder, there are Giant Runes. My druid has the fire rune. Through that, I've allowed him to use any Fire spell of any school that druids can use with the idea he's concentrating through that rune. Now throughout the adventure other runes can be obtained of varying elements and such, and If my druid got ahold of one, I'd allow other elemental mirroring spells to be prepared by him.
So, why am I doing this?
I'm a huge fan of flavour and uniqueness. Sometimes at my table people make "builds" and make basically carbon copies of the tried and true optimized builds they've seen the community put together. I'm not shaming them, but I like showing people you can still not do max DPR or have every answer and continue to have fun. If my druid can't do all the normal druid things, doesn't that mean my party can fill the gaps I have? I think that creates party cohesion which I really enjoy!
Now does my druid hold the party back? Not at all, as a Shepard Druid I have minionmancy on my side which has saved us a couple times now, whether through immense action economy, the body blocking of enemies, or the pure utility of it. For the last reason, I have already conjured giant badgers to make a pseudo excavation team! Further, I'm still a druid with healing spells as well and when combined with a certain totem spirit, I've a very potent healer in critical moments.
Thank you for attending my TED talk ;)
TL;DR I've made a druid use basic druid spells and conjuration spells only- while dipping into full druid list with use of magic items. I can't do all druid stuff, party has more agency to help, also forced to problem solve better. Lots of shenanigans and good times.
This was something touched on with a few wizard UA schools, but it is always fun to see it popping up again. The idea that all casters cast the same is actually a misconception born of laziness, and even the PHB mentions that all people cast magic differently. It is why as a wizard you can't just pick up a spellbook and learn the spells, because each wizard calculated how to manipulate the weave in different and personal ways that, while translatable, are different for each person.
I'm a big fan of at least, if not changing the description of how a spell actually behaves like you did, having some interesting descriptions for verbal or somatic components. Maybe part of how you cast cure wounds is to tickle someone lightly, or casting fireball requires you to do a Kamehameha impression. Just saying you cast eldritch blast is boring, but what if you aim the shot with your pinky finger? This may apply less so for other classes, but if you are a paladin at least maybe come up with a single sentence prayer for casting protection from evil and good.
Magic only feels samey between casters because of people being too lazy to customize the description as you are suggested to in the books, rather than it being a mechanical problem.
P.S. WotC please give us more tables, in general, but especially for coming up with cool spell descriptions.
TL;DR Magic is only boring because people are too lazy to describe what they are doing and if they acted it out things would be a lot more dramatic than just saying "I cast fireball".