I agree with everything my not-at-all foolishsailing friend writes.
If the boat would be too big without thrusters and electric winches, I urge you to consider the possibility she is too big.
Keeping systems running is an entirely different proposition for people who are circumnavigating compared with those who sail in a particular part of the world, and even people who are highly talented at fixing things themselves sometimes struggle to keep up.
The more sophisticated a piece of
equipment is, the less likely it can be fixed at some random location on the globe.
And until things are fixed, you don't want a boat which is more of a handful than you would otherwise have chosen.
Most sailors will disagree, especially on an
internet forum. But not many sailors circumnavigate, and those who do are not generally spending lots of time online.
Evans Starzinger and Beth Leonard sail a big boat, but not as big as you propose.
They are unusual in being
serial circumnavigators who nevertheless find time to spend online. I suspect the reason they have spare time is partly because they look VERY hard at each "nice to have on board item" in the light of experiences such as this:
Three-quarters of the way through our circumnavigation, we experienced one of those rare epiphanies we all hope await us just over the horizon. After five months and 8,000 nautical miles of
offshore sailing, we tied up to the International
dock and started fixing the boat. We replaced a broken spreader light, rebuilt all our electric pumps, repaired our broken
diesel heater, re-wired our
navigation station, replaced the zincs in our
refrigerator, installed the warranty replacement
parts for the electric autopilot…
Two weeks later, friends of ours on a 30-foot, 30-year old
fiberglass boat tied up alongside us. They re-bed their forward
hatch and went sightseeing. When they returned a week later, we were still fixing our boat. Just about everything we fixed, they didn’t even have aboard—and they didn’t miss it.