sorry for such a late answer, we usually play on medium or hard. however, this aim issue made me search some knowledge 
. here is what i found in sources:
zzwolfsp-read-only/src/game/ai_cast.c
if ( g_gameskill.integer == GSKILL_EASY ) {
newent->health = client->ps.stats[STAT_HEALTH] = client->ps.stats[STAT_MAX_HEALTH] = 1;
cs->attributes[AIM_SKILL] = 0.6;
cs->attributes[ATTACK_SKILL] = 0.6;
bzzwolfsp-read-only/src/botai/chars.h
//skill when aiming
// > 0.0 && < 0.9 = aim is affected by enemy movement
// > 0.4 && <= 0.8 = enemy linear leading
// > 0.8 && <= 1.0 = enemy exact movement leading
// > 0.5 && <= 1.0 = prediction shots when enemy is not visible
// > 0.6 && <= 1.0 = splash damage by shooting nearby geometry//attack skill
// > 0.0 && < 0.2 = don't move
// > 0.3 && < 1.0 = aim at enemy during retreat
// > 0.0 && < 0.4 = only move forward/backward
// >= 0.4 && < 1.0 = circle strafing
// > 0.7 && < 1.0 = random strafe direction change
bzzwolfsp-read-only/src/game/ai_cast_fight.c
aim_skill = cs->attributes[AIM_SKILL];
acc = cs->attributes[AIM_ACCURACY];
// fretn
if ( g_gametype.integer <= GT_COOP ) {
if ( g_gameskill.integer == GSKILL_EASY ) {
acc = 0.5;
} else if ( g_gameskill.integer == GSKILL_MEDIUM ) {
acc = 0.75;
} else if ( g_gameskill.integer == GSKILL_HARD ) {
acc = 0.9;
} else if ( g_gameskill.integer == GSKILL_MAX ) {
acc = 1.0;
}
what i meant by ai's aim is it's accuracy (as i understand, currently 0.5 on easy level of difficulty).