Other Weaknesses:
Reiko is human, and thus she is subject to any and all human frailties, such as illness, sleep deprivation, starvation, or death. While she is in good physical shape, she can be though of as having a weak constitution, which is what the exhaustion from Avatar battles is usually passed off as if they occur in a public space. Although she has trained herself to deal well with people, naturally she is rather shy and introverted, and this means that outside of work or professional situations she often has difficulties speaking with or dealing with other people. Coupled with moments of Expression, she tends to keep to herself in her personal time rather than have to deal with people or reveal her own true feelings.
Although quite powerful in the AIDA dimension, she is not as adept at using her emotions as any form of shielding or protection. The emotions necessary to do that are ones that are not fully developed in her, and thus they are weaker which requires her full concentration to block, leaving her unable to do anything else, but can also be penetrated easily. Thus when she is actually hit, she can take quite a bit of mental "damage" and is often knocked off her feet. Similarly, if her mind wavers in the slightest during a combo she can be thrown out of it. While her Avatar can block with its massive wings, this is only a temporary shield which can also be broken through, plus while she is blocking she cannot do anything else and her speed is reduced to a crawl. Due to her lack of eating and sleeping proper amounts, as well as taking more damage due to her imperfect blocking abilities, she tends to succumb to battle-related fatigue more often - and rarely rests the required amount to fully recover even when she does.
The key to undoing her ability to project lies in her need to avenge her brother. If somehow Amagi does die, whether by her hand or not, that need will be filled and her subconscious will be put at ease. While not doing it herself will leave her bitter and empty, the desire will leave her and she will essentially be forced to retire from her job.