Considering they are meant to be average at everything, and to help make them less bad, I was thinking maybe offer them more skill points?
Alternatively, give the base class bonus to concentration and disc? It's a bit weird to me a barb, ranger and paladin can match them.
Fighter skills definitely seem like a tight spot and a big thing that keeps me from wanting to play them, and I think skill points are a big factor in the heavy multiclassing that even Pure Perks aren't necessarily holding people back from doing
Some ideas that come to mind would be:
1) OUB Pure Fighter gear with bonuses to certain skills
2) +1 to concentration and discipline for each level of fighter (lost if not pure?)
3) more base skill points? 4+int?
I'm currently playing a pure fighter, and where I struggled is in levels 1-6, there is a large amount of scavenging you can do for resources, but the Search skill is untrained. Sadly, it is not worth the cost with the minimum skill points the fighter gets.
I am on board with cmenden 3rd choice.
My only recommendation is to make Search part of the Fighters trained skills.
for what it's worth fighter suffers from stat dependence by way of having low base skill points and several skills that they directly benefit from.
ie, int gives them skill points which they lack and perhaps borderline need which makes it so that playing a fighter with 12 or 14 int is preferable to playing a fighter with a lower int with a reverse investment in anything else.
this also makes it undesirable to invest points into something such as persuade, intimidate or whatever as you will ideally be saving skill points as much as you can for more utilitarian skills such as spellcraft or tumble despite your investment into intelligence. if you are playing a non-human you can just forget it.
paladin suffers from this and more