when I play sonic, I have to time my tiny little no hit box jab to meet an arching projectile thats coming at me at varying speeds. its easier for me to just power shield it, but now pika is running at me and im shielding,
ikes jab is fast, has a massive hitbox, and makes him lean forward so its super easy to do and requires no timing at all because you can hold A, and then after you clash, the best move to use against a pika that is trying to rush you while you deal with the jolt is just to jab again. the process is a lot simpler for ike than it is for anyone else in the game.
ikes use up smash in a position where there opponent is above them trying to get down. it out ranges every aerial in that position, out lasts airdodges to the ground, and can catch pikachu out of skull bash and quick attack, which makes him not use them, which limits his movements. pikachu with limited movement is not nearly as scary.
pikachu when he has ike in the air is at a great advantage because he can frame trap with jolts and up airs, and ike cant get around thunder easily. and if ike quick draws to try and get away pika will still catch him and punish just as hard.
ike when pikachu is in the air, is either throwign out big, high range moves or waiting to punish your options to get to the ground. if pika airdodges an aerial, he doesnt have the airspeed to use that dodge to get close enough to punish the aerial, so it resets the situation to neutral, where ike is at an advantage.
at neutral ike is +1, when ike gets in, its +2 for ike, when pikachu gets in, its -3 for ike.
Does that make it more clear?
Also, I feel that the CG doesn't do much for the matchup. getting the grab requires you to navigate the minefield known as ikes jab range, and all you really get out of it, is the same damage you would get on any low percent situation with pika.