Complex electrical system?
Why would a SD-20 backup alternator and a direct battery connection for at least 1 pump not provide redundancy for any single failure? It's not a terribly complex system.
An extra alternator, wiring, and battery(?) does add weight and complexity. Simple as that.
I meant full electric for the fuel pumps only. The plan is to build a very simple carbureted day-VFR aircraft with steam gauges. I did splurge for the electric elevator trim
and will certainly fit wingtip & tail strobes/landing light(s) for better visibility in the pattern.
I hear you but since you are going to have to add a backup alternator and systems to feed your electric pump, you might as well look at all the other options.
Here is something to keep in mind...
Some day you might want to sell your airplane. Having a non-standard aircraft system, especially something as critical as your fuel system, might make your RV very difficult to sell.
My mentor built his -6A with an “H” engine and rather than having a bump on the front of his cowl to accommodate this oddball engine, he put a fuel pump in each wing root. To switch tanks he simply turned one pump on and the other off. He had a backup battery to feed his pumps, just in case.
On takeoff he would turn on both pumps, just in case one fails. That is not really any different than the rest of us.
However, after he passed on (natural causes), the new owner of his plane installed the engine driven pump and moved to a more “standard” fuel system before he would fly it. The family sold his beautiful -6A for much less than market value because of the fuel system. The buyer was local and had the skills to modify the plane.
Just something to think about.