Swordmage is Renaissance (almost science) Guy and so some of his skills will and should be physical along side the mental ones is that a rational that works,?
I think that the question is more to do with the class getting an unusually high number of skill slots rather than the range of skills that it can choose from.
DBW has reiterated quite . . . emphatically that it is a scholar class like the Wizard with access to the Ritual Casting ability rather than a more martial or skill-inclined class. Hence you would expect a similar number of skill slots to the wizard, with rituals covering some of the out-of-combat utility that a class would otherwise use skills for.
1. Renaissance (almost science) Guy sounds to me like quite a different concept than is being designed by OP. This concept could work but feels a little conceptually weak IMO.
I believe that part of the concept of the class is from some of the renaissance fencing schools. These were generally grounded in solid martial principles, but with a layer of mysticism or mathematics (science!) layered over it to hide some of the secret principles of the specific school, and to appeal to the fads of the time. (Like someone might slap "
Ninja!" on something in the 1980s-90s.)
So you have longsword schools that use a poem as a mnemonic device to help an initiate remember the principles, but which would not make sense to anyone else.
Or the fencing school mentioned which derived its principles of distance and movement from the proportions of the user. - Distance between feet for the stance should be this geometrical derivation, for a lunge should be that etc.
(Also included: A
serious level of passive-aggressive snark regarding how long a sword should be. Thibault was Not a Fan of the trend towards increasing sword length of the time.)
To the uninitiated, these principles, and science in general would be lumped together with magic as part of Natural Law. Hence why you could romanticise it into a magical class in a similar way that earlier medieval knights were romanticised to have supernatural powers derived from their faith leading to D&D's paladin, and the warriors of the Orient becoming Monks.
2. Having 2 skills from the class already allows for a mix of physical and mental skills.
Yep. Plus backgrounds.
I'd want to see a little more right now. Assuming it's a null-caster, it's got a basic fighter chassis with a scaling armor feature and the tome warlock special invocation. The Aegis and the point based maneuvers are doing a lot of undefined work, so it's difficult to evaluate without a little more flesh there.
Maybe more like a Fighter with the Ritual Caster (Wizard) Feat as one of its bonus feats.