If Machamp is a big tank having to slowly navigate his way in but does HUGE damage once he's close enough...
Blaizken is a jetliner. He can hang back one minute and pelt the enemy with Heatwave projectiles, then the enemy makes one off decision and BAM!! 30-40% of their lifebar is gone.
You have to be a risk taker with Blaziken. He has plenty of unsafe options, and his good options whittle away his HP. Doesn't matter. If you're aggressive and determined enough, Blaziken CAN get in and deal big time damage with a quick combo or two. And it's not like he has no safe options either. His enhanced specials tend to be safe on block. Forward Y is faster than his other Y attacks and make for a good poke. Up X actually puts him at advantage on block (the screen emits a yellow flash when this happens), and you can transition into an air dash. Enhanced Heatwave is a great pressure tool and beats out Counterattacks when timed correctly.
Then there's High Jump Kick which pierces Counters and can be reused on block if you dash. Flare Blitz has super armor AND pierces counters, but it is generally unsafe on block. Brave Bird is always a nice get in option whether it's the normal version that can be used to dodge an attack and retaliate, or the enhanced version which is a fast and brutal hit. And finally Sky Uppercut is basically a Shoryuken in every way.
In short, Blaziken has some ludicrous burst options and actually benefits from being played rather recklessly. You still have to play smart though. He doesn't get through everything, can still suffer against projectile spam, and being too reckless will end him fairly quickly. He's also a strong candidate for worst Counterattack in the game. Short ranged (boosted in Burst Mode) and doesn't lead into anything (before you think "Gardevoir", she can actually move her counterattack around, and it's a combo starter).