I'm confused. I don't think the wildshape ability, or stats from the change, affect the barbarian abilities.
Let's say you had a Druid with this set of stats : S 8 , D 8 , Con 8 , I 15 , W 15 , Cha 15
Then he Wildshapes into X and this happens (via 5esrd) ...
"While you are transformed, the following rules apply:
Your game statistics are replaced by the statistics of the beast, but you retain your alignment, personality, and Intelligence, Wisdom, and Charisma scores.
OK so to multiclass into or out-of Barb, you have to have S of 13.
You re-work your stats. Now say you decide to Wildshape.
Some of the forms have a Strength
below 13.
And that's a problem, because you would have insufficient S
to have multiclassed in the first place. Something happens here.
It isn't clear rules just yet. It might be bad, or it might be really bad.
Easiest homegame thing to do is avoid it altogether, and just not
run up against the question at all.
Barb + Druid multi doesn't pick WS forms with S below 13,
it picks one of the small pile of other forms with S above 13.