Since Ryder is a novice,non-military, will it show him/her learning weapon skills and such?

You're equating gameplay mechanics to lore, and doing so across characters, platforms and stories. That just doesn't work.

I was going to go into some mechanical detail, but Cypher largely addressed the main points. Shepard started the OT as an N7-- That's N (Special Operations) 7 (highest proficiency rating)-- with an impressive service record. By comparison, we don't know either Ryder twin's Alliance Vocational Code; but it's likely not overly impressive. They each had relatively short, uneventful careers.

Shepard was gimped at the beginning of ME1 because we were starting a new IP. It happened again to begin ME2, because we reset the combat system, and "returned from the dead". If you imported a save file into ME3, though, Shepard was an unstoppable force of nature from the opening minutes of ME3. This is the Shepard to whom you really need to compare the young Ryders.

Scott or Sara will become very capable, but they won't begin the game this way. They'll begin the game as young, former marines with special training and biotic potential. That's pretty damn impressive, but nothing next to an N7. If we get to see Alec in action, side by side with our fresh protagonist, the difference should be made manifest.

Even at high levels, our new protagonist won't surpass Shepard, really. My ME3 Sheps were all versatile world-beaters. Rivaling or equaling Shepard in power, though, isn't so bad, is it? As you say, it's fun! Besides, N7s, and those of their sort, have to come from somewhere. There will be other badasses like Shepard, even if they never face anything like the Reapers. With MEA, we get to start the journey of a new badass.