I've played a friend who uses Reptile. In my opinion he's top tier. He's got everything. Good damage. Amazing pokes. Mix ups. EVERYTHING. How do you stop a character that is safe on everything but his dash? He's got great armor. He seems a bit extreme. What are his bad match ups? What or who destroys him? Leave your comments below and any advice is appreciated. I use Liu Kang Dragons Fire and A-List. I don't think Cage does well with Reptile. Liu Kang for me gets beaten by Reptiles SAFE ARMORED moves. And he loses the air game.
I only know my side of the fence, but I'll do my best:
-He does have everything, particularly Deceptive. Reptile's lacking in extreme weaknesses. It's little stuff.
-I'll immediately contradict myself by saying that while he
does have zoning, it's not great. Reptile has great ground speed, but can't teleport, so in tandem with his shaky zoning it makes characters with strong space control and projectiles (Shinnok, Grandmaster Sub, etc.) headache-inducing. Raw forceballs can be punished pretty easily, or at the very least avoided to gain ground for free.
-Reptile's only safe armoured move is EX Invisibility, in Deceptive. Everything else is -15 or worse.
-In my opinion, Reptile's air game is on the weak side--his anti-air is great (if he has meter
don't jump), but his aerials come across as ghetto Sub ones.
Reptile does it all--assuming he has meter (though he's better than he used to be at building it). Since you're having issues with his armour, look to bait EX db2 /db4 to keep him honest--the stronger your punishes, the better, since if he breaks you can keep him dry. If you pick up good zoners (or low fireball all day with Liu), Reptile has to get more calculated with his meter to keep the pressure on. Eating an EX bf4 in long-range situations loses you the battle, but wins the war. In regards to blocking mixups, expect the overhead when he's running dry--b2 is incredible and he needs meter to convert from b3.
Learning Stunt Double might help. I can't say for sure, but it strikes me as something that could deal with Reptile better.