I kinda wish some things were pulled out and/or split and put into a separate trees.
A basic "Survival" tree could enhance all aspects of survival to a point. The survival tree might enhance cooking speed and decrease recipe requirements overall to a point. The cooking tree allows a player to further increase this and specialize into cooking. Each of the spec trees (Agility, Strength, etc) unlock recipes for special boosted foods related to their trees.
Repeat for crafting. The survival tree might enhance crafting speed and decrease recipe requirements overall to a point. The crafting tree allows a player to further increase this and specialize into crafting. Each of the spec trees (Agility, Strength, etc) unlock recipes for special items related to their trees.
Repeat for mining. Let strength increase mining damage, but also put some block damage in survival tree and put some block damage while mining in mining tree. Throw increased returns into the Mining tree. For someone to fully maximize, as with all the trees, they would need the basic Survival tree perks, the Strength, and the Mining.
For other things, skill percentages could be split up. For example, health. In Fortitude, divide the benefits in half. In the "Survival" tree, you can increase your max health, health regen etc... but only to a point. You go into Fortitude to enhance it further.
In Agility, the speed and movement benefits could be divided in half. In the "Survival" tree, you can increase your max stamina, stamina regen etc... but only to a point. You go into Agility to specialize in it and enhance it further.
Maybe half of the backpack slots are opened up in the Survival tree, but if you want to maximize this, then you need Strength.
Same can be done for almost anything. This allows players to improve their characters in all areas for survivability reasons without committing to a build and weapons set. The current system is very binary. Sure, tie these things a spec tree, but only to maximize and specialize. You should be able to enhance your character somewhat in every area that any player would need to survive without forcing full commitment. Particularly in single-player, a player needs to be well-rounded in skills at least to a degree. From there, choosing specialties should enhance some area and provide niche abilities.