eh, not horrible. my JS 1aB is inconsistent, but my combos are pretty consistent. She has a few aGi's and I'm not sure what they all defend. Gi's are so specific it seems...
You can safely ignore aGI's since most of them(out of the entire cast) are terrible and you almost always have better moves to choose from. aGI's are what you do to your friends who are new to the game :)
Well, Tira's GS 4x5B leads to HUGE damage (for me so far anyway) and it has aGi properties. I can't really tell what it impacts though. It impacts mids, but not all mids. Idk how the aGi moves work lol but I'll take your word for it, and try to avoid most of em, 'cept for her GS B+K, and the 4x5B, it does too much dmg to ignore lol
Tira's GS 44444B aGIs all high attacks, I believe. The aGI window starts about 6 frames in, but I'm not sure. Her B+K aGI is good against aggressive opponents and reactable mids that people like to whore out, like Astaroth's 22B.