(keep in mind ezreal CANNOT use his ult with it...It's magic damage not physical damage the triggering condition.)
Eeehh, a bit overtly doubtful. Sure it sounds like it would make sense but all the other choices out weigh the BC choice. The characters that abuse trinity force may sound like a candidate for the item but one of the reasons those character really like the WHOLE package of trinity force will not give up things like sheen chain procing.
The ADc Champions that I can see using BC is very limited. It's mostly looking at ADcs that LIKE phage but NOT trinity. Which for the ones I play I can see the most likely two being Sivir and Lucian.
Sivir because Phage is double stacking unto her passive. If she is in an actual duel situation she is the adc that extends fights by spellshielding an important ability of the enemy, but still has the team fight weight of bouncing her blades everywhere pre-cleaving everybody within range.
Lucian because he can stack it a bit fast for the average adc, because of his passive. The auto->dash->(passive)auto->q->(passive)auto to hit max cleave stacks of 6 for 30% armor negation can be done very quickly. His ultimate can also stack the cleave effect very quickly and make it more viable to use vs fleeing brusier and tank weight champions.
Otherwise...The characters that use trinity won't give it up. but all those luxury phage purchasers will want it for sure.