What the first Q's' collector connections do is bootstrap out the Ccb's, making the input C very low at midfrequencies. It will as well produce a negative input Z at sufficiently high frequencies though, so beware.
A more brutal direct connection of collectors, putting zero volts C-B across the input devices, is shown in Feucht's book, Handbook of Analog Circuit Design.
Another advantage: reduced power dissipation in the input devices, and opne which is roughly invariant with signal level. However, this still leaves the output devices' thermal distortion to contend with.