I agree actually that dicerolls are a *** way to handle things. The point I'm trying to make is surveys are currently uninteresting. Starsector is absolutely though, a game about risk management, choice and consequence - right now, neither system carries very much of any; you could just as easily argue they currently serve no purpose beyond gaining you brouzouf (How much is, again, currently determined by a "diceroll")/a ship. Short of what I suggest, or even less realistic, making surveys a minigame or extension of the game its self, I don't see any other way of changing that.
As for salvaging, let's say for example, you come across a derelict, but salvageable Onslaught. But, it's floating around in hostile territory, and has 4 D-mods. In addition, you're on a procurement mission that will expire in 4 days, 2 days away from your destination at best speed.
Now, with the current system, it's a no-brainer. So long as you have the crew and resources the system determines you need for the salvage operation, it's as simple as "Consider Ship Recovery" > "Recover" > Done. You now have an Onslaught in your fleet, but haven't increased the risk of being caught by pirates, and haven't come any closer to your mission's deadline. All you have committed to it can be expressed as elements of a spreadsheet.
Let's say then that with this system, recovering a ship of such size takes a day. Now this changes things; If you commit to the operation, not only will you be losing out on that day to complete your mission comfortably, but you also further increase the risk of failing it by staying stationary in hostile space to carry it out; an attack by pirates will interrupt the process, and possibly land you in a fight you could only hope to run from - meaning you might end up losing most of that day, then attacked, and possibly lose a ship or several, with nothing to show for it because you took a risk and it didn't pay off.
Planetary surveys are consequence-free to a similar degree at the moment. Right now, it's based around meeting the criteria for a given planet, then that's it. When with a more in-depth system such as the one I suggest, there is room for players to determine their own criteria beyond the bare minimum. "I can survey this planet" turns into "I can survey this planet, but".