I just looked through all of the episodes of Season 3 of TNG, and barely half of them dealt with any kind of strange new life or civilization. The rest all dealt with trips to Federation colonies or outposts of some sort, Klingons, Romulans, Q, Ferengi, or crew members' personal issues. Q, and the Ferengi did start off as new life, but by Season 3 that really wouldn't apply to them any more.
Let's look at the first 10 episodes of season 3, shall we:
Evolution - begins with the Enterprise observing a red giant, plot set in motion by a science experiment
The Ensigns of Command - a diplomacy mission
The Survivors - answering a distress call, research for the strange phenomena
Who Watches the Watchers - literally about doing research on indigenous people
The Bonding - plot set in motion by an exploration mission on a planet
Booby Trap - Enterprise doing research of old asteroid relics
The enemy - Enterprise answers a distress call
The price - the auction of a wormhole - that is important because it leads to new exploration in the Delta Quadrant (but is mostly a diplomacy mission - I give you that)
The Vengeance Factor - a diplomacy mission
The Defector - a diplomacy mission
Out of the first 10 episodes of Season 3, there are two episoded starting with the Enterprise answering a distress call and four diplomacy missions. The other four episodes (five, if you count the wormhole) have plots that are either directly set in motion or set during the Enterprise doing scientific exploration and discovery.
Yeah, there are rarely plots about people wandering around and drawing maps. Where is the plot in that? But as it stands - doing scientific research, exploration and discovery - is the main motivation for our heroes in about half the episodes. Not even counting those where they research the situation after a distress call. As I see it, "discovery and exploration" has a big part in that season. As it has and always had in all of Star Trek...