.....Why if i want to be and evil warrior can i not join them

Basic
It would have been brilliant if you wanted to be the shining paladin then you could happily join with the Fighters Guild. But like me if you sometimes wanted to feel a bit darker or a little evil you could join the rebellious Blackwood Company.

Role Playing
I love the world of OB and i love even more the ability Beth. has given us to immerse ourselves by role playing. I have a Swordsman type character whose family were slaughtered by the Fighters Guild. Johan wants revenge and seeks the Blackwood Company. Johan has no luck when trying to join them. (BECAUSE OF BETHESDA)

My story could have been brilliant

Does anyone else feel the same about the BC or in a magical sense Necromancers??

If you're on PC

http://tesnexus.com/downloads/file.php?id=17448

Yes, joining the BWC would be nice. Since you can't (in vanilla) however, there are some things you can do with a little imagination. Do the FG questline until you infiltrate the BWC, then simply do not progess the questline any further and enjoy life with your BWC guildmates.

You have to admit, "BAM" was a pretty good entrance......... right?

Yes. And if OP is on PC and up for mods, he would be well advised to check it out.

The Imperial Legion is another faction that should have been joinable too. Infiltrate the Thieves Guild and arrest the Grey Fox, or siege the Dark Brotherhood with an entire legion would have been cool.

The Blackwood guys are really messed. Just kill ‘em all, and get over it. Go back to trashing O gates.