I personally prefer 24 players servers. 32 players servers encourage players to spam nades, rockets, and whats not. With extra 8 players in the same area, that spam whatever will hit something sooner or later. It was the main reasons, I believe, Valve removed the grenades in the first place and later reduce the ammo counts for soliders and demomen. Just my observation.
Regarding the final point on Gold rush, the offensive team has only two ways to enter the final area, and spamming rockets, nades, and anything else with almost infinite supply of ammo from spawn areas makes it really difficult to win at the end. It is actually somewhat similar lay out as the final point in the Dustbowl so I expect you all will see more final explosions eventually.