Force is about balance, but mostly it is about contracts. It deals with different parties coming to a mutually (un)desirable agreement, and agreeing to be bound by its terms. Force does not include outright aggression, but it does include acts of violence that are legitimized as means to hold individuals to their word and enforce contracts. Cassiel likes only clear, explicit contracts where all parties have informed consent and the ability to reject the deal, but his god also presides over implied social contracts. Dadga is accepts the use of force as valid so long as popular consent says that it is valid. In reality systems of laws and courts have very little to do with Junil's sphere of absolute justice and authority, but rather with Dagda's sort of compromise.
Mind and Metamagic are opposing spheres, but it is easier to see in them the complementary nature that all opposing spheres were meant to have rather than how they conflict. They both deal with knowledge, but knowledge of different sorts. Mind deals with the future, whereas metamagic deals with the past. Mind tries to predict what will happen and manipulate it to fit subjective preferences, while metamagic is focused on remembering the past and dealing with data objectively. It deals with being aware of how you know things, so that you don't wander off into delusions.
Floating Eye does seem more like an Octopus Overlords spell and I have argued in the pas to move it back there, but its actual effect of uncovering forgotten knowledge of the landscape its the sphere rather well. I guess dispel magic has to do with how knowing how something was done helps you undo it. Perhaps the sphere also helps you gain the knowledge of how the gods wrote the laws of physics that govern Erebus, which is useful to those that wish to bend these rules. Djinni are canonically elementals that Oghma created, but they seem like they might fit better with Ceridwen. They don't have much discipline, but can do great works of magic because of their ability to move freely between and channel mana from various planes. Mortals are almost always limited to channeling mana from within the plane they inhabit. There is a lot of mana in Erebus, but it pales in comparison to the concentrated pure mana of other planes.
Ceridwen is really the goddess of connections. As goddess of dimensions she deals with relationships between points in space, but she is really focused on relationships between people. The pain she represents is not physical pain, but social pain. Physical torture does not matter to those dominated by her sphere, but the fear that no one would love you if you went against the expectations of the group is huge. Her sphere causes us to ignore the thing itself (or the person itself, even your own self), and view it based on how it is used. We forget who we really are, and focus on what it is that we want and what other want from us. We insist that others fill the roles we want them to fill. We care too much about approval from from others. We enter toxic codependent relationships. The bonding provided by her sphere is a crucial part of love, but if taken too far does not permit love because it excludes consideration about who the loved one really is or what is in his personal interests.
As the spheres themselves are personified, her abilities related to human interaction also extend to relationships between raw elements. She does sometime allow those who serve her access to other planes, but channeling deals with her mostly because it deals with manipulating the relationships between elements.
She may have access to world beyond Erebus and wish for Erebus to end, but a plan to destroy it by breaking the fourth wall? Come on. This isn't Yu-gi-oh: The Abridged Series.
