This is very true! Nobody is arguing that it is not a fun and interesting fluff decision.The double sword is now 1d6, and is no differenty from dual-wielding short swords, damage-wise.
And what is "optimal"? That depends on the character concept. Do you want to maximize damage? Then this build is sub-optimal. Do you want to build a peasant hero or a martial monk-type that kicks butt with a staff? Then this build is optimal.