Well Nanaly main shine is black unit can use skill asap, and ok this is my experience only the reason i dont like bashira aw skill is it reduce her atk and there plenty of high def enemy out there -.- (and geting 5/5 skill is pain).
Overall its true this increase her dmg output, but sigh.....it become even more situational when to use it.
Although Bashira main shine in this aw skill is not the xtra shot..... But the cooldown on her skill which can be reuse fast enuff
Lita main use is deploy her outside heal range and use the skill, since she not gonna be targeted you don't even need to worried about her and she can keep shooting ranged enemy without worries of being hit back.
I also love the extended duration and that 1.2x atk is the most important part. Combined with her aw ability (15% chance on double shot) sound good to me.
To me archer need to be above 600 atk to help killing big enemy as well, since their aspd already fast enuff they need the atk power to bypass enemy def
Spica aw skill? what can i say love it

while its true the lose of range and duration can cause some problem, but a high atk archer with fast hit become magical is great.
Just becareful not to press her skill on enemy with high MR, there plenty enemy with 50+ MR out there