So which hand is ACTUALLY holding the wheel at this time you're changing gear and indicating?
With indicator stalk on the right, your right hand is loose to operate the indicator, and your left hand isn't on the wheel at all.
You say "It's more economical to keep speed constant, that means changing gear and indicating at the same time"
However, if you was inidicating, you're preparing to turn, therefore you would be slowing down, which is probably the reason why you're changing gear, so you wouldn't be keeping a constant speed.
And it is also much more economical to plan in advance and use the engine to slow you rather than a lot of brake.
If you're going round a roundabout for example it's easier to keep your hand on the gearstick, same when accelerating, you can still indicate with your free right hand.
If it was just one gear change there would be no problem
How about when parking, constantly changing between 1st and reverse, if you need to signal then you don't have to waste time moving hand back and forwards between the stalk and knob
1 hand on steering wheel while accelerating and driving around a roundabout?
WHat happens if you get a puncture or a blow out, sorry but with 1 hand on the wheel you're not going to be able to control it.
2 hands on the wheel at all times unless you're indicating or changing gear.
I don't understand why you constantly change between 1st and reverse when parking :S