If my memory serves me right, I remember Elop telling in some interview in the summer of 2011, that even if WP7 would flop, WP8 then would be in par with the competitors hardware. But if Elop has told investors then that WP7 will save Nokia already and Nokia sees no big risks in WP7, then the lawsuit has merits.

Nokia has known since 2010 that WP7 has restrictions, which make it incompatible with modern SoC. If Nokia hasn't told this openly, it may be a bad thing, depending what court in time will say.