Can’t imagine you’d save much weight, once you’ve added those clunky Italian sprockets (which is where the poorer shifting comes from) and the chain device you now need.
More cogs at the back and thinner chains just seems to mean components don’t last as long.
My 3×9 setup has been faultless since 2000, with lovely evenly spaced jumps between sprockets.
Never had a problem with ground clearance myself, but I appreciate other people might (I’ve always ridden HTs).
Front mechs are far simpler than rears.
With regard to change, the only actual improvement made in changing gear I’ve witnessed with current systems compared to my old gear is that when changing to a smaller sprocket or chainring, the shifter now moves when you pull the trigger rather than release it.
If you go down the Italian sprocket route, they are lighter than the rings they replace.
What chain device? NW chainrings and clutch mechs do the job. And if you do need a top guide they weigh nothing.
If you need 27 gears then that’s cool. It’s just not for everyone these days as there is a ‘choice’.
My 1×10 gets me up everything and down everything. The bike is silent too, which adds to my enjoyment 😮
