Yeah, Conor is kinda honest in the way he fights, he expects his athleticism to be enough even if his opponents can predict whats coming.
What also sucks for Conor in this match up is that one big weapon Conor has is that he can land a sweet counter against his MMA opponents and he relies on that skill plenty. It worked beautifully with Aldo but if he thinks he is actually going to be landing counters on Mayweather he really is delusional. So, his 1-2, as you say, is close to useless, his nice, sharp counters work against lower opposition and with smaller gloves to get the quick KO. Floyd is not lower opposition and will be using 10z pillows.
So yeah, he has to look at the castillo fight, the maidana fight, the de la hoya fight, then say "ok, where am I getting the cardio to emulate that for the duration of the fight?"
Not happening.