You should pretty much always take Medic imo. Also looting buildings becomes way better when you have light source )lighter) + crowbar + strength + breathing rag.
That is actually pretty funny.
No matter which forum you visit, you always get a lot of claims like "you
have to take skill X, or else...".
And that probably for 50% of the skills
Me, I would say that Mechanic is such a "must have". It just makes scavenging 100% safe (with slightly less success chance, but once you get lighters and a crowbar, it doesn't matter). My character is harmed only in encounters.
Honestly, I think that no skill is mandatory and each combination is possible. Though there are some that will give you a harder time.
For example, my current character has neither Botany, nor Trapping, making finding food VERY rare. And also no Ranged, making hunting almost impossible.
Still, I am at day 12 or so. My tactic is to go scavinging enough to sell, buying loads of food in the mall in DMC and use that while outside, scavenging.
And sometimes, I do get lucky encountering some feral dog.
One design gripe I have is that there is only one way cure to Blue Rot for most characters:
... and during the whole encounter, afaik only one path leads to your character getting the cure (which also makes you immune; you even want it when not infected). So choosing that path is a must, as everything else pretty much means certain death due to Blue Rot. Well, 2/3 actually, but who wants to take that chance with an advanced character, seriously?
So, pure neccessity destroys any roleplaying here.
Blue Rot is just too much a certain death condition. And not one that can be protected against reasonably (yes, gas masks work, but you cannot always wear one). Sooner or later, you
will meet someone who is infected in a situation where you have no protection and that is it.