There's been fewer new suggested skills/spells recently, so thought I'd throw one in the mix for the dedicated warriors out there (open to debate whether pure dedicated, or warrior as secondary class) - I like the dedicated only option personally as they're probably more in tune with someone who has spent years training and honing their fighting skills, as opposed to picking it up as a secondary hobby...
Blind-Fight (pre-reqs third-attack if dedicated only)
As part of their advanced training, the Warrior is taught the ability to sense, perceive and react to movement/attacks using all of their senses, as opposed to relying sight alone (e.g. cue usual movie scene with hero being trained by master to learn to fight whilst blind folded etc). Impact of mastering quality of skill is reduction in AC impact of not being able to see (e.g. due to 'blind' or 'gouge'), and the ability to identify/target an individual with whom you have engaged in combat in that or earlier rounds, as you can still perceive their location, movement and attacks using all of your senses.
