Sounds like the same problem I had with one of my LE. There was a batch of E2s where the ferules in the LE came loose because the rods weren't cleaned out properly before they were glued in. This resulted in the ferules moving (slowly) and leaving insufficient length in one of the rods (in my case the lower LE rod). The force on the ferule is transferred to the rods along the length of the ferule but concentrated at the end . . . thus if there is insufficient ferule length in a rod the end of the ferule will eventually bust out the wall. It sounds like this is what happened in your case. Thus when replacing the rod make SURE that the ferule is fixed as well with half into each rod (should be at least 2-3 inches)
As for using regular carbon instead of P200 . . . I tried that, it's much 'bendier" (not as stiff) giving the kite different flight characteristics especially in high wind conditions (read tip shudder). I wouldn't recommend it.
As for reframing it with different rods, since I replaced the one LLE (and fixed the ferule) I have been unable to break anything else despite continued abuse (it's my 'beater' kite). In fact on several occasions I have done tipstabs that bent the LLE 90 degrees without any further adverse effects.