A shorter mast means you got a shorter lever from the wings up to your center of mass, so yes it will be more lively indeed.
Say you got a 100 cm mast, and board 5 cm thick, and your center of mass is about 100 cm over the bottom of your feet typically.
This means the "lever" is 15 % shorter if you use a 70 cm instead of a 100 cm, thus a bit more agile indeed, although not as much as the difference in mast length
It might be me, but I find myself LESS agile on my short 83 cm mast, than the 91 and 100 cm ones
I know it sounds odd, but the thing is, when on the 83 I have to spend all my focus on NOT to go too high, thus I can not crank the the foil like with the longer ones, where I can lean hard into the turn (sometimes drag my hand in the water) in fact almost no matter how much chop there is.
Even worse, I dont wanna turn hard, mentally because I know I might ventilate
If you dont care about supershort touchdowns with the edge or corner of your board, I can see how shorter masts might work, but I have found the opposite as said, that I can NOT crank as hard with the shorter ones.
And I would simply HATE if I made an ever so slight water touch with any part of the board
So I have found that I can turn more radical with the longer ones, eventhough the lever of the shorter ones should give you a slight advantage in this very respect yes.
Or it could be me being too lousy at this, I know
Just a very different view than most maybe ?
It is ambiguous - the short ones has a bit more liveliness indeed, but you can not crank over as hard in turns on a wave (or flat water), besides having less safety margin of course.