Yeah, I would agree with Sophie. You might get mood lighting out of cans but that's about it.

Yes and no. What do you want the light to do? Enough light to walk through the room, watch TV, do needlepoint, read? Do you want the ceiling to look like swiss cheese? Do you want soft cool cave-like lighting, or bright room expanding walls and corners? Do you want the room to feel like the ceiling is too high for the room size, or bring the light down where it is more proportional to the room?

For the most part, it will be our tv room. In one corner, I'm thinking of making a reading area, but I can put a lamp in that area.

A portion of the second floor overlooks the room, so reducing the ceiling height isn't an option.

Would wall sconces provide adequate lighting?

Wall sconces are indirect light, usually. That means that the majority of the light has to go all the way up to the ceiling, and then bounce back down to light the room, needing even greater lumens to light the room to the same level.
Usually, a combination of lighting is needed to give such a multipurpose room the right lighting for each occasion. The only way to design the lighting is with a floor plan of the room and surrounding rooms with the intended furniture placement in the rooms to scale.
Lighting is subjective and can vary by the intended uses and a person's age, as well as the wall, floor and furniture colors.
The question that needs to be answered first is 'what do YOU think adequate lighting is?' Give some examples that are relevant in your current home. How many lightbulbs in your current bedroom seems like enough light to you? What is the size of that room and how tall are the ceilings? Don't forget to determine the type and wattage/lumens of the lights you are comparing.

The desired light level could be anywhere from 10 to 40 lumens per square foot if ruling out intricate tasks. This is still a fairly wide range. That could be anywhere from 12 to 40 recessed with a very high 1200 lumen output each for that high of a ceiling.

Curious what you ended up doing and if it worked, we are building and have a similar room.