Leopold said:
in the end it ups the damage a rogue does if/when he hits on par with a fighters weapon spec. and mages spell focus.
uhh... no.
The rogue gains a new d6 every other level. The improvement of 1 die type is roughly equivalent to a +1.
This equates to +1 for every 2 levels.
At fourth level, this MATCHES the fighter. The rogue gains +2 and so does the fighter.
Every odd level after that, the rogue improves yet the fighter spec feat stays static.
This is just simply better.
Now, if you are in a game where, lets use 11th level for example, the rogue gets a lot fewer sneak attacks, then it might average out.At 11th level, the rogue is getting 6 dice of sneak. If ONE attack in THREE is a sneak, then he is gaining about the same per shot average.
That is a big if. in my experience, watching the rogue in my current game which is in mid-12th right now, his sneak attacks make up 3/4 or more of his attacks. HE rarely takes non-sneak attacks. he will find some of his other options more palatable than the non-sneak damage (like healing or using spells from devices.)
So all in all, this feat would make a greater benefit than the fighter's class specific specialization would.
it seems imbalanced when compared tp PHB feats. it might be right spot on when compared to other third party feats, they seem to be in general a little overboard. (I am sure it helps sales to be just a little bit more.)