Kipor or Honda generators versus engine driven alternators?

I see two or three problems with a 'normal' generator setup.

1 - I want 1 or 2 litres of petrol on the boat, in the 4-stroke
outboard and that's it.

2 -Traditional generators involve lots of mains potential ac floating
around the boat.

3 - Unless you lay out 30 to 50% extra for the electronic, smoothed
output generators you run the risk of destroying sensitive electronic
equipment like laptop power supplies and microwave timer mechanisms (
or so I'm told )

4 - Running a 37 kw diesel to extract 50 or even 100 amps at 14 volts
is notoriously bad for the diesel engine, very inefficient and noisy.

5 - running a generator to drive into the shore circuit to charge
batteries via a mains 100 amp charger is a reasonable idea but somewhat
inefficent.

So I did some thinking and my idea for the boat is as follows.

I'm keen on placing a small inverter close to each piece of mains kit (
just the microwave at the moment ) and sticking to battery potentials
in general elsewhere. This means that I can use the microwave even
without the generator running.

It also means that I have to find vast amounts of charge and surplus 12
volts nominal from somewhere.

Leave the engine alternator in place and use it for the starting
battery except in emergencies

Put in a modest ( 25 amp? ) but good 4 stage mains driven battery
charger running from the shore power circuit.

Then I want to use the motor from a Kipor diesel generator to drive a
regular 120 amp marine alternator via an alternator managment system.

Upside - no mains voltages floating around, 1/2 the generator system
becomes 'standard' the alternator, regulator and charge management
systems are all replaceable anywhere ( just about ). The system is not
too sensitive to the engine running speed ( if the governor goes
haywire i can at least hold a constant throttle position and still get
a charge. ) There are no frequency matching problems - all kit is still
DC, except that driven by inverters. In a breakdown situation I have
the main engine alternator as a backup system.

Apart from the engineering challenge ie matching my alternator to the
kipor engine, I really cant see the downside to this type of
installation.

Any comments from the group?