The number of signings under Murty and Caixinha was probably comparable in numbers to Gerrard though, at least, it wouldn't be far off anyway.
I think Gerrard has tried to get a balance of potential vs. experience. For example the players you've quoted in Balogun, Defoe, Davis and McGregor are also balanced with signings like Kamara (24), Barisic (27), Aribo (24) who are all yet to hit their prime but are internationalists with their countries and have good immediate sell on potential.
Then you have slightly younger players like Kent, Hagi and now Itten who they will be hoping to develop and eventually sell on at a profit as well.
I think he has had to bring in more experienced players, certainly in the early days of his Rangers career, to try and get consistency.