So a strange thought occured to me while writing one of my fics. It's obvious none of the main six are combat oriented ponies, only fighting if they have to, and of all of them, violence is least likely to be Pinkie's forte. But is she actually the most powerful of the ponies, maybe even more powerful than alicorns? Yes her magic was drained and didn't turn Tirek into his mega form, but from what I could tell, Tirek didn't get quality of or type of magic, just sheer volume.

Pinkie seems to be a master of spontaneous generation, can manipulate time unconsciously, can shape shift on a whim and can subsist on a diet composed almost entirely of sweets (got to be a power there by itself, one I freaking want!). Sure she's the first pony you'd want to meet, but anyone else wager she's also the last one you would want to mess with?

Pinkie is a force of nature. She is will incarnate. She is the ultimate expression of mind over matter. She takes that which has no substance at all and turns it into inescapable weight beyond the influence of even the longest lever. She stands before the cold indifferent universe and shouts laughing: "Behold the truth which I have given you!"

Two words:

Party Canon.

Sure, Twilight has her magic, but her combat abilities are questionable at best given how little she's been able to do with it. When push comes to shove, Pinkie's rugged earth pony nature and her spontaneous abilities make her the most powerful in combat.

Pinkie works on Rule of Funny, though. It's why the Grimdark Future version of her was just a really strong earth pony. All the odd stuff she pulls off only really works if it's humorous, so it isn't something she'd really pull out in a fight.

4941025 To measure Pinkie Pie's strength, I would suggest that is comes from friendship and tecniqes.
Of course, she is wise beyond her age and reason, and all her power is apparently not linked to the mark as was showed in the Cutie re-Mark episode. On that note, even Human Pinkie Pie is apparently using magic even before Twilight is applied to the equations.
Going by Type, Pinkie win her type.
Rarity isn't on the field, while Twilight has power and potential enough, if she is applying the right trick to the situation.
Dash could be great, if permitted to do her specialities in the right time, and Fluttershy needs failry close range to do anything, unless you trigger the Mane-iac Hulk, in case that is permitable here?