Lions and Tigers and Bears…and Wolves and Orcs and Dragons and Demons and Aliens and Cyborgs and Vampires and Werewolves…
I’m going to suggest that you actually need to repeat that type of exercise on a regular basis when GMing GURPS . Why? The temptation to bring in more complexity “because you can” will be ever present. Fighting that temptation is key to running a successful campaign and avoiding choice paralysis in GURPS.
Choose a Limited Number of Themes
Instead, consider choosing to focus on just one or two components of a setting–even if the setting has a lot of possible choices. For example, I might decide to run a magic/occult focused Dark*Matter campaign (I’m not). I would be better served ignoring most of the other possible campaign themes rather than trying to build in everything the setting can offer. My adventures will be crisper and–if you’ve talked to your players–the PCs will be more suited. Which brings me to…
Help Your Players Create Relevant PCs
In a GURPS campaign that could suffer from choice paralysis, the GM isn’t the only one to experience it. Each player will also have to decide what kind of PC to make. That can be overwhelming. This is where the GM must step in and help. Do not be afraid to “limit” the PCs. Most players will thank you for it. If you dare to say “just make something you think will fit” you will end up with a disparate group that will have a hard time engaging in logical adventuring together. Instead, create campaign character guidelines and circulate those to your players.
One of the issues that has come back up is related to GURPS’s notoriously detailed skill list. We discovered that a PC had forgotten to include a point or two in Computer Operation. A strict reading of that skill indicates that someone with no points in it literally cannot use a computer. For any adult in TL8 Earth, that actually takes some doing (assuming the adult is FROM a TL8 area of Earth, of course). Even if you don’t use full templates, providing lists of required skills–or even just giving away a free “everyman template”–is super important for a successful GURPS campaign. Otherwise you may end up with players complaining about their PCs’ inability to perform basic tasks (like drive a car).
In the Final Analysis
The GM has to be the game master from an early stage of any campaign. In GURPS–a system known for its flexibility–if you don’t make decisions early and often, you will end up in a morass of indecision and confusion. Even if you want to include everything because it’s “cool,” doing so will only limit the chances of a campaign success. Remember, you can always run Season 2 of your campaign and include things the second time around.