Interesting thought...
The problem is that there are no pits in metroidvanias. However, there are some traps and obstacles that could be instant death if you don't have the proper equipment. For example, there are two areas in the first castle of SotN lined with spikes, but if you touch them, you only take some damage. In OoE one of the areas is a swamp with muddy spots on the ground that slow you down. Why not make those instant death scenarios. Spikes = instant death with out certain items and with muddy areas, you sink and if you don't get out quick enough, you sink to the bottom and die. Now then, these can be pretty easily evaded, but it would be appropriate punishments for people who aren't paying attention, especially if the programers place save points far from these obstacles. Another change could be that you take significant damage if you fall from a very high place.
These are just my thoughts, but metroidvanias could use some instant death obstacles. It's something they lack and should really be tried.