I did a small research today and checked how many projectiles does it take to kill an average character in various fighting games.
HDR- 10/11/12
Both Ryu (blue fireball) and Ken vs Ryu. Number seems to be dependent on the type of fireball used with the HP fireball killing faster than MP, which kills faster than LP.
SF4AE2012- 16/18
16 for Ryu, 18 for Ken. Both were against Ryu. Doesn’t matter which button you do the fireball with.
SFXT- 15/16
15 for Ryu, 16 for Ken vs Ryu. But remember that this is just one lifebar! Again, button doesn’t matter.
Guilty Gear XX Accent Core- 13/15
Ky’s stunedge against Sol. Ground stunedge 13, air stunedge 15.
Melty Blood AACC- 13
Checked Aoko’s various fireballs (236A for all moons + 214A for H) against F Aoko and all did the same damage.
Arcana Heart 3- 11/13/18
Checked some Arcana projectiles against Love Weiss. The Lang Gong fireball killed in 11 hits, Love laser killed in 13 IIRC, and the Wind boomerang killed in 18.
TL;DR: Projectiles in airdashers are not that far from good old SF2 in terms of damage, way closer than modern Capcom’s take on SF.
I won’t measure chip damage because in airdashers the guard bar plays a big role and basically takes the spotlight from chip damage.