bst in party situations? well the only abilities that stick out to me are Gerard's tp moves. Corrosive ooze is 33% attack and def down on the mob. These are huge boons to the whole party. Blu's are happy to get the -33% def debuff in a new spell.
Purulent ooze for the first 10% of NM's life is quite nice for a party also. They are rather unique abilities that bst can bring to the table. BSt used to be uniquely capable for crowd control... but that was around charm.. and not very practical now.
I can't think of any other bst abilities that are particularly good for a party.... Killer Instinct... but thats been there for awhile.
Also, don't forget that hippogryph is also an avian... and its a sweet dd pet.