Apparently I put too much value to the name.
I disagree that an Animal requisite is not necessary for Eyes of the Cat.
You cannot just invent the minor ability out of nothing. You must change the target's human body in such a way as to give the ability. Humans do not naturally see in the dark. Some animals do. So you give the target the ability to see in the dark by transforming his eyes into those of a cat. Ergo an Animal requisite.
For comparison, if you were casting a spell to give him eyes in the back of his head, then you would not need an Animal requisite, since humans can naturally have eyes. This would give the target the ability to see behind his back.
In short, MuCo does not create a new ability out of nothing. It modifies the target's body in such a way that he gains that ability. The ability needs an appropriate medium. If that medium involves body parts that are not part of human nature, then you need a requisite of the appropriate Form.
For Eyes of the Cat I agree - IMHO The granting of the minor ability guideline is geared toward exactly the eyes of the cat spell and there are other cannon effects which are similar. It's not a miss print. And it makes sense that the spell is using Animal eyes because of the requisite and name.
That said, other higher guidelines should be able to grant similar powers without the Animal requisites as long as the change makes thematic/setting sense.
Not sure what to make of the T:Ind vs T:Part. Cannon has examples of both. Blarg.
It very much depends on how you read it and what base guideline you assume.
Are we working with
Level 2: Change someone to give them a minor ability
Level 10: Turn a human into a land animal (with an Animal requisite)
If the latter, then sure you need the requisite and likely need T:Part to transform just the eyes into, literally, cat eyes. If it's the Base 2 spell, then nothing suggests a requisite is required. The Magus is simply transforming his eyes to be the equivalent of a cat's. Making one's skin scaly and green doesn't mean literally transforming into a crocodile. The text about Cat's Eyes should be understood as a cosmetic effect shouldn't be penalized. One could title the spell something like "Enhanced Night-vision" but that would just sound boring.
Thanks to all for your answers. I have found one thing that perhaps could be usefull to clarify te problem. The spell "The Unseen Porter" claims to be similar to the "Unseem Arm" but it can manipulate heavy weights:
THE UNSEEN PORTER
R: Voice, D: Conc, T: Ind
Like Unseen Arm (ReTe 5), but it can carry
large objects such as crates. Roughly speaking,
it has the capabilities of a very strong person
(Str +5). The heavier the object is, the slower
the unseen porter moves. If delicacy is
required, high Finesse stress rolls (12+ or so)
are needed. The spell can only carry inanimate
objects, and cannot carry you. It also cannot
lift things more than 6 feet above the ground.
Casting requisites of an appropriate Form for
the target are required.
(Base 3, +2 Voice, +1 Conc)
Could be possible that the size (or mass) have a role here? In other words, for a reduced effect, the base can be reduced as well (despite the initial statement)
Take note that it is exactly the same spell but the base is 3...