Maki has to turtle against Blanka. She can fight him fairly decently because her Crouch Fierce rapes his Jump (then again, her Crouch Fierce seems to mess up lots of people’s jumps…). But she can even walk up to a Blanka Jumping straight up and down and get off the Crouch Fierce, unlike most characters.
If Blanka does a Blanka Ball, an instant Running Slide (Fireball + Kick, Forward Kick) will catch him.
The biggest problem is that from the front, Blanka’s Crouch Fierce rapes all of Maki’s fun running games. So if you do plan on attacking Blanka… it’s tough. You can come off the back wall with a QCB + Jab, but Blanka’s Air to Air priority (esp. with that annoying Jump Straight up Fierce) usually gives him the advantage in this situation. Basically, the best way to play Blanka is to play carefully. You have to reduce your typical “sporadic” Maki gameplan and resort to careful pokes from the front. Fireball + Fierce is good for Blankas who sit there and do nothing (at the right distance, of course), as well as getting in some instant Running Overheads (Fireball + Kick, Roundhouse). But as I said, Blanka’s Crouch Fierce will kill that all, so you have to pick your moments.
So Maki can fight Blanka if she turtles, but Blanka can fight Maki better if HE turtles. Not a fun match-up on either side, really.