If they changed the oblivion's stars, I would break down and cry, I loved the black and purple ones...
And if the whole "duh" thing is some way of insulting my intelligence, then I kindly ask you to provide a reasonable explanation as to WHY they would decide to change the stars for the oblivion, which fit quite well in with the colors of the blade, and change it with ones identical to the oathkeepers, which is basically opposite in color, please, enlighten me...
The only other explanation I can think of is perhaps the stars are different color because of some ability (kinda like when you use Sonic Blade in KH1, the stars are like blue-ish purple and yellow), but even in that case, they made the stars different from that of any keyblade... I don't see they would use the same stars for two fusions that use two different keys though... (Still thinks the oathkeeper is hidden in there somewhere!) xD