What should we expect of bread as a healthy and practical staple?

Healthwise
The crust
It would be fair to say that all and any burnt food may be carcinogenic or  cancer promoting. That this is due to the formation of acrylamides is probably hypothetical  http://bit.ly/1CcqHau . Frequency of exposure is likely to be a factor especially where a staple is involved. and that the likelihood of this being the case will depend on frequency of exposure. In the case of  a staple, which bread is, this is really significant. In the case of bread, the great smell when it is just cooked  and the inviting colour, taste and crunch of its crust is from the mixture of caramelised or burned carbohydrate, protein and fat. The cooking of any dough or batter will produce a skin but this need not be a crust, the result of  burning.
Cancer of the oesophagus is on the increase and the burned crust might contribute a mechanical irritant factor as well as chemical one, as we tend to bolt our food, bread especially.
This skin of bread can be pleasantly chewy without being burned by thoughtful cooking of the dough. Patently the dry air of conventional bread ovens reach very  high temperatures to produce this  cindering of the bread's surface. Moist air from a steam oven will conduct the heat to the dough at a much lower temperature achieving a set without burning, and, incidentally, at a lower cost.
Such natural nutrition  as in bread, as opposed to its fuel or energy value, is likely to be protected by cooking at lower temperatures. Vitamins, enzymes, aminoacid and protein complexes are definitely changed and probably damaged by oven heat so less of this is better. The gut protective nature of fibre that is in the dough will be diminished by cooking - after all this what cooking is mostly about and not peculiar to bread.
The dough
No wheat, no or very low gluten, no or low salt though high potassium salt would be a sensible replacement and no yeast,
Potassium and not sodium bicarbonate for leavening will the sodium content low.
The use of  psyllium will provide set and cohesion, and will contribute very significantly to the fibre content with any other non - gluten grain and/or nut content. No added vitamins so there is no illusion or belief that they are there unless it known that they will resist the cooking temperatures.

From practical point of view.
Cost
As it is hoped that this new bread will qualify as a staple it must be affordable for the poor. Pucker breads are often cxpensive even if they are wheat based.
This is a difficult one as the cheap grains, wheat and barley, are precluded on their gluten content.
The cost of most other grains will be greater, not least that they are less accessible at outlets but because the shear bulk of wheat pasture, at least in Europe, offers the economies of scale. We are beholden to find healthy but cheap expanders for our dough. Husks, hulls, and bran from a range of non-gluten grains could be considered. Such are usually very high in fibre and that is what we want.
Taste
It has to taste good. We have spent most our lives inured to the taste of wheat in that it use in bread and every thing else that has wheat flour but rarely ever intrudes into the taste of the sugar, salt, spice and other additives in those products. Other grains will tend to do this so they will take some getting used to.
Texture
This should be liked but importantly it should have something of the cohesion and 'return' or springiness we find in standard bread.
It should hold together when sliced - it mustn't crumble when this happen and the skin or outer should be dry to the touch.
It should taste great when toasted - here I am talking against what I have already said by way of
acrylimides but toasting can be barely a colour change.
It should have a reasonable shelf life, especially in the fridge and it should freeze well.
Shape.
The dough should make buns, and other forms for interest. Most important that it will form a sandwich loaf - long and squarish.