Leblanc a good midlaner ?

Recently I have been using Le Blanc and I find that she stomps when i play against Ahri or Orianna but is she a good all-around pick ?

She's really solid at winning lane if your opponent is a squishy.

She's awful if your opponent decides to go full-yolo and throw someone like Mundo, Irelia, Nasus, or god forbid Galio against you. If LeBlanc can't 100%-->0% her opponent she's pretty useless. Especially if they have solid sustain and just keep healing back to 100% every time your burst is ready to go again. (Almost every fighter has at least decent sustain).

LeBlanc also lacks the pushing power to roam without giving something up, and the only reason to pick LeBlanc is to dominate during the lanning phase. A LeBlanc that didn't get a snowball going in lane is one of the most useless champions in the game. Most AP Carries can shave off a solid 50% of the enemy team's collective health in one QWER combo, most assassins have the resets and AA power necessary to take out 2 opponents by themselves. Marksman can go all the way to 100% of the enemy team's HP if they're protected/positioned well enough (50% is more realistic with a solid performance in an average game)

LeBlanc can easily find herself in a situation she can't even 100%-->0% the enemy support if she's behind, and even ahead - she's often only capable of taking out 1/5th of the enemy team's collective health.

Because LeBlanc's team-fight potential is so awful late-game, your opponents aren't really loosing anything by running an off-pick in mid to deal with her.

is she a good all-around pick ?

She's the opposite of all-around.

LeBlanc is an incredibly specific pick that has all her power placed in 100%-->0% assassination potential.

You pick her to win lanning phase so hard you demoralize your opponents into surrendering at 20, or win so hard your entire team can just push to win at 25 minutes.

That, or you pick LeBlanc to feed off very separated teams. Either from yolo queue tactics, or your entire team carefully controlling vision and cultivating an assassin's playground of an environment where you can reliably find picks and isolated targets, and push the pick-comp advantage to it's fullest.

Anyways, LeBlanc is pretty high-risk, high-reward. Very specific power spikes and playstyle.

She's not a generalist that's good all-around. That would be Orianna - very well-rounded, plenty of back-up strategies, and pretty consistant power distribution rather than jagged power spikes.