Hardness of edges is always a compromise, since the solution is to increase the number of polygons (facets) in a model. Rounded edges, as on a pillow, will increase the polygon count dramatically, causing potential problems with PC memory/ processor speed available and resulting increased render times. You can import high polycount objects but you run those risks.
There are several other factor that affects it too:
The most important, probably, is the lighting used and surrounding reflective surfaces. Just one light for example will give harsh shadows, especially if there are not adjacent, light coloured walls, for the light to bounce off. Additional lights, discreetly placed, will create a much softer effect.
"Basic" render is of course always hard and, as you already realise, Advanced rendering is much better for inside renders because it uses the bounced light off internal surfaces.
The quality setting can affect it also. I always do final renders at level 5 to make sure the full 'bounce' effect is achieved.
The Antiailias setting should be set to maximum - 4 (if you have not already done that).
It is possible to take the model into other rendering programs and possibly achieve a better result but obviously involves additional steps and, with some programs at least, a reassignment of textures etc, so not a viable alternative for me. I have usually found that additional lights gives a much softer result.
All that said, I agree with you, if there was a quick 'push button' way to do it, it would be great!