Yeah...that's a little short-sighted on the part of the GC. As you said, pavers are one option as is stamped and stained concrete. I think all they need is a thin layer to do the stamping/staining and they can do it later, so you can have time to think about it. That's what I did with my front porch and back patio. If you get a good concrete person, they can do amazing things with both color and pattern. Mine looks like natural stone.

I don't think this is up to code and I'm surprised this even got past your home inspector. He is liable for that if he did not specify in his report that it wasn't up to code when you purchased the home. I believe you have up to one year from the time of inspection. That's your first issue. Next, my main concern would be curb appeal, and how your changes are going to have an impact on your investment. What is going to look better for the next buyer when you try to sell the house? I would not do a pergola or trellis. A pergola is more suited for a patio area, and a trellis is only going to cheapen the look of your home, and most of these have to be painted. That means long term maintenance. We've done so many renovations on our home, and made a lot of mistakes because we tried to go the cheap route. I would call around for contractors - I can't imagine that a new concrete slab on the front will cost too much money. My neighbor has a huge front porch that he had completely done over along with his front sidewalk and steps, and he paid less than $5k, and what you have is a lot less. I would just expand or replace the concrete slab on the front to make it wider - maybe just a foot or so on each side - it will give the illusion of a bigger house with a wider porch, put railings around the perimeter and up the steps, and you can put one concrete planter on each side of the front porch (one in each corner) for symmetry and curb appeal. In the long run, you will be happy you did. If that isn't doable, I would at the very least replace the stairs with concrete steps going up to the porch, and widen them. They should be at least as wide as the door frame. It will look much better than what you have. You could also try adding pavers on each side of your walkway leading up to the porch. That would look nice too.

Your problem appears to be caused by settling under the stoop and walk. Unfortunately, that is common in new builds because the concrete is poured before the backfill has settled. And, the concrete may have had too much water in the mix causing its strength to be compromised. Most likely the deterioration of the brick is a by-product of the above caused by water seeping through the concrete. Have any neighbors had similar problems? What do you do? I would check with a good mud jacking company and I would also speak with a quality mason. See what suggestions they offer. Replacing the sidewalk isn't a big deal but the stoop should be looked at for a solution, not just a cosmetic repair.

Photos of our steps. It's mostly porch but there's a side stoop with the stone top. Sorry about the dust, can't bring myself to wash the steps since we're in a drought. Now that I think about it, the concrete risers were not actually sacked as the architect had specified (rubbed finish to remove air holes and imperfections) but there is some kind of applied finish. The concrete folks put samples up on a grade beam and I banged those up before choosing one. Your slate is really pretty. Good luck!