An engagement where one side brings lots of fleets of small wings and one fleet of large wings may be unbalanced because the enemy doesn't know to prioritize attacking large dangerous wings over small ones and will waste time maneuvering and waiting for tactically useless engagements against tiny fleets.
Since individual wings take time to get hunted down and destroyed (invaders move between orbitals, defenders move between orbitals, everyone is chasing somebody else and nobody is using opportunity fire) an attack or defense strategy that uses many tiny fleets will extend combat engagements a lot if no long-range units like starfrigates are present. This is especially true for against enemies with short firing ranges, since their window to engage targets is significantly smaller.
This is highly exploitable, see this post.
Prior to an attack order being accepted, merge all allied fleets into one "virtual" fleet for the purpose of assembling wings?
Or rescan for targets every few second and reject tiny fleets unless nothing else is available.