BA almost merged with KLM and Sabena in 1990, and came very close with KLM in 2000. The first probably failed due to regulatory hurdles which had largely been removed by 2000. The second failed due to inability to agree on the respective shares of the resultant cake. BA's pension burden probably played a part in this.
Diplome, I suspect that this two-way merger (forget AA for the time being, that's just a commercial agreement) will have very little efffect on crew costs and conditions for the foreseeable future. All the early benefits will be in head-office and support functions. Even after six years I suspect there has been very little convergence amongst AF and KLM cabin crews (although I stand to be corrected by a couple of prominent Prooners).