Let's see... just a couple of years ago, Marvel time (X-Sanction), Cable was nearly killing the Avengers... FITS RIGHT IN! Seriously. Seems like a lot of True Blue Avengers start out this way.
Deadpool... eh... not so much... but he's unquestionably changed from what he was back in the 90s. These days, he's like a Wolverine-Spidey love child without claws. So... whatever.
And imo.... better 'an Stark.
I'm not really a fan of either of them being Avengers.
Neither seem an organic fit. Deadpool has an especially murky past, and whilst I accept that he is largly reformed and dont have a problem with him acting as a hero, the Avengers are supposed to set the gold standard for heroism - something he doesnt fit.
Cable is a soldier, but the Avengers are not an army so he doesnt really fit IMO. He's also used to acting without oversight and has a pretty murky pasty of shady dealings himself, as recent as the last X-Force series. again, he's undoubtedly a hero, but not Avengers material.