Buffs are not frail.
If there is something to be fixed, it's not the durability. It's the "all-or-nothing" damage model that needs to be fixed. 30mm shots to the tail are gonna blow humongous chunks off and eventually cause the buff to crash, but it doesn't mean the whole rear section just snaps off and the plane is thrown off balance like we see currently in AH.
With better damage modelling we'll see something like this when 30mm shots are to the tail: chunks of tail section gone, and the Lanc noses down.... it begins with a shallow and slow dive at first, then the angle becomes steeper, and the Lanc wouldn't be able to nose up nor slow down and eventually airframe falls off and crash.
...
But, anyway, buffs are not frail.