Honestly, basketball was about even before BC, Miami and V-Tech left. Once they were gone, the Big East dropped their two weakest teams in Miami & Vtech who didn't even make the last Big East Tournament due to their inability to win that year. They then ended up being pretty competitve their first year in the ACC...that sums it up.
As for f-ball, the Big East was better with Miami, BC, V-Tech, SU (who was still pretty decent at the time), WVU, and Pitt until Miami, BC VPI left. At that point, I'd say the ACC became slightly better but not much. For some reason, 2 of the 3 (Miami and BC) never really panned out as expected. In fact, has Miami ever really made it back to the glory days?