Always hated the "Magic can't grant you a cutie mark!" and "Magic can't fix your mane!" meanwhile magic can mind control a whole town, change the age of any pony, ban a creature from a certain place, turn a pony into another creature and of course the time travel. How come magic can do such op things but can't draw a picture on a pony's flank or make some hair appear on someone's head?
(I never said that cutie marks are just pictures. I meant the fact that nobody ever drew a LITERAL picture on someone's flank, fake cutie mark, with magic paint)

Discord is the best example of being as powerful as the plot need, because he can bend reality around his finger but can't stop himself from lossing his magic.

The strongest earth pony can shatter boulders
The strongest pegasus can break the sound barrier
The strongest unicorn can freaking time travel and alter reality

Regarding the question of why Twilight doesn't use Want-it-Need-it on villains, I would assume it's a case of magical ethics. Yes, the Want-it-Need-it spell is very strong and could probably be used to defeat some of the show's villains (assuming they have no defense against its influence), but I don't think Twilight would be willing to use the spell for that purpose even if she thought of it in the heat of the moment. Generally, mind control magic in fiction is considered evil/dark magic, and a good character like Twilight would be disgusted by the notion of using it to manipulate people, even villains. Yes, she used it once, but that was in the middle of her having a psychotic breakdown and not really being in her right mind.
I think it's safe to assume that spellcasters in FIM have some kind of moral framework/philosophy around the use of magic that we the audience are not aware of. That's also why Twilight isn't seen using Dark Magic again after Season 3, even though she was taught how to use it. It simply wouldn't be ethical.

The biggest issue with magic in my mind is how almost all of the unicorns we meet in the show have incredible magical abilities, yet we are also told that most unicorns in the show’s universe don’t have the ability to cast much more outside of the basics like levitation or magic related to their cutie mark. Rarity is best and pretty much only example of what is considered the common unicorn as we only really see her use basic levitation magic and gemstone finding spells seemingly unique or natural to her. Twilight, Sunset, Starlight, Starswirl, Trixie, Sunburst (kinda), and the princesses all have cutie marks based around magic, so we mostly see those ponies and their magic abilities, not what is considered normal.

The way I saw equestrian magic-
Every spell has a formula, but not every formula matches the spell’s difficulty.
A teleportation spell might have a complex formula that takes young unicorns a while to memorize while a time travel spell might have a much more streamlined formula.

This would also lead to Some spells simply being more difficult to physically cast than others, and may effect those not trained in magic or not tied to magics niche. (Non magic cutie mark)

As for obscure plot contrived spells, I dunno.

And then there’s Sunburst.. he knows more than more ponies about magic and can’t do many spells

The only real consistent rule in magic is that more often than not, magic creates a problem that makes an existing friendship problem worse. except if there's a villain, then you need to go get the magic doodad to blast them out of existence

7:08 this is funny because in the MLP Roleplaying Game Zecora is a spirit of Magic just like Twilight. Okey sure, she is an alchemist that brews potions but she has a non-zero spellcaster score. What's funnier is that the book tells you that if you dont want non spellcaster magic ponies in your party, you can give the Magic perk for free which implies every earth pony (and pegasus) can cast a spell.

It just works

Saw Glimmy on the thumbnail and had to click.

Magic gets so absurdly over-powered in later seasons, I swear.

Pegasi and Earth Pony bros, it's over for us...  😢

This is why unicorns are the master race... except in G5, I guess.

According to Faust, Celestia put a "cork" on Twilight's magic when she was a filly. Yep, her Boast Busters performance is TS with an active limiter on her. If anything, in s03+ canon Twilight is downgraded, because all other unicorns suddenly started doing Twilight-exclusive stuff, and Twilight herself is tired after rotating a few animals in air for a minute.

This is why I write magic systems that are, well, weak (by comparison).

My main character can do telekinesis, make magical fog, and cast a locator spell that will find nearby items similar to ones they've already seen. That's it. That's their entire spell list. Any expansion to that list will be a major event for their character. But you'd be amazed what they can get done with those three spells.

I prefer a character who makes the most out of a limited toolset over a character who has infinite tools but forgets to use them when it really matters.

I think Glimmy being well versed in esoteric spells doesn’t mean she’s *stronger*. For example stealing cutie marks and the time travel spell are things Twilight can’t do, but Twilight can still easily block Starlight’s laser beams with ease.

The short answer on why the princesses don't teleport away, or magic the villain away, is because then we wouldn't have the show.
And because logically speaking, we are not only shown, but TOLD directly by Zecora AND Starlight that magic requires concentration.
Twilight was literally going to teleport all her friends out of the way in Cutie Map, but didn't have the time to concentrate on teleporting 6 ponies away. In the early seasons, we see her slowly gain confidence in teleportation. Her first ever time teleporting herself was in the very first episodes, and then throughout season one she teleports like 2 feet just because she can. We're even shown through Sweetie Belle that magic is difficult because to her, a broom is very heavy. Granted, we aren't really shown her magical growth after that, but she does gain control over her horn SUPER quickly. Notice how Rarity never teleports herself? Because she doesn't have the magical ability TO do that. She can levitate objects, and find rare gems, but that's the extent of her magic.
The princesses are shown to be "weaker" because, frankly the show is about Twilight and her growth in magic and friendship.
And the time Celestia DID help, Chrysalis was so powerful after draining Shining Armor of his love for Cadence and overpowered Celestia (she even said that out loud).
I do think the writers could have put more thought into magic as the seasons went on, because it sounds like Faust had a pretty good idea for what she wanted in the earlier seasons, and after she left it was thrown out the window. The later seasons in general (7-9) all have pretty lazy writing and really bad inconsistencies, and completely ignore established bonds (Dash and Rarity), abilities (magic as a whole), and personal character growth (Trixie and Fancy Pants)

A interestingly grounded take. Maybe the weird, nonsensical, unhinged nature of the magic isn't a bug, but a feature. Never thought about it that way, but it's an interesting thought for sure!

We can also remember the fact that the Element of Harmony can give powers to non-users, like it happened to Sunset Shimmer

I always figured Twilight’s magic in boast busters is part of how ‘friendship is magic’. Some of those really strong moments come out when her friends are being seriously threatened. In this case, all of Ponyville

And then there's Discord. Plot hole or plot device Discord.  He's way too powerful for the show and I like it because sometimes the writers take creative ways around it. He's too powerful to the point that someone might even take his magic, that's why they made his magic exclusively for himself! I like the idea that discord is not a malicious being that wouldn't hurt anyone, even if it means getting rid of a villain!