Upgrading residential wiring
Actually, metal conduit is better and potentially safer for a few reasons:

Grounding

Everything needs a grounding path. If you use non-metallic cable (aka Romex) or wires in a non-metallic conduit then you have to include a ground wire (green or bare). If you use metal conduit and metal boxes then the conduit does double-duty as the ground. This actually has an additional benefit because a loose hot wire inside metal conduit or a metal box is likely to short to the conduit or the box and trip a breaker. A loose hot wire inside PVC conduit or a plastic box can cause all kinds of problems.

Fire Safety

There are two main hazards with electricity - fire and shock (which can go as far as electrocution). Metal conduit and boxes are inherently safer when it comes to sparks and fire than plastic. Metal can burn, but only at a much higher temperature than plastic such as PVC.

Life Safety

If everything is installed properly, the exposed conduit will all be electrically grounded, so it is really quite safe. Most incidents that would result in a circuit that includes the conduit would trip a breaker pretty quickly. But there are exceptions, which is where GFCI protection comes into play. GFCI is typically required in kitchens, bathrooms, garages, outdoors and any wet areas. It can be added everywhere if you are really paranoid, though keep in mind that an unnoticed nuisance GFCI trip on a refrigerator could result in spoiled food, and an unnoticed nuisance GFCI trip is far more common than an unnoticed over-current (regular breaker) trip.
I'm not sure why you are not a fan of wires inside walls. Done properly, they are quite safe. AFCI protection is now required on many circuits (gradually increasing to &quot;almost everything&quot;) which takes care of a lot of the possible &quot;hidden damage to wires inside walls&quot; issues.