I am a 115 warrior 'with 15723 AAs. I am struggling tanking in RoS zones with my 109 WIzzy box. I am wondering what AA lines should i be focusing on and how should i think about using my AAs and Discs
15k aa's is kinda low at 115 for sure. Browse thru the available AA's and you want to buy those that raise your armor class and mitigate the damage you take. You need to be around 30k before you can really feel comfortable in end group zones. Plus your gear matters, obviously. No class is more gear-dependent than warriors.
There's a decent video about tanking as a 115 Warrior on Youtube under this title: Everquest: Thoughts on Modern Era EQ Tanks and How I set up and Play a Warrior.
I play a warrior as a box toon and if I don't play for awhile, which sometimes happens, I get rusty and this video helps with the basics, although even he admits he's not a master warrior. But for tanking in the group zones, and assuming your puller isn't always bringing in 4+ mobs at once, this video is more than adequate. For survivability you want to go sword and board (i.e. with a shield) and it's nice if the shield procs one of the Vector of Health levels, where you can heal yourself every time you get hit.