Last summer, I had a BB and FD packages booked, and after doing some initial math, the BB saved us a LOT for 4 Disney "adults" (by a lot, I mean more than $1000)! Disney had already released their special 4 Day Magic Ticket, so I dropped the package tickets, made my BB a ticketless package and purchased the 4-day magic tickets. They released these tickets in March, for stays April through September, so maybe wait until March to make a decision?
Also, make sure to price out not just generally where you are going to eat, but also, if you currently have a package with tickets on the BB, price it out with a ticketless package (dropping the tickets) and purchasing the tickets from UC. If it's about the same, I prefer to not have the dining plan, because it gives us more flexibility on where to eat (for example, having a lighter meal with an appetizer or at a lounge if we're not too hungry). But, again, if the 4-day Magic Ticket would work, I would wait until March.