Str or Dex scaling weapon for PvE (Ng+)?

Right now I am in a bit of a predicament that I could use some help with from more knowledgeable folk. I began playing on my first character again after taking a break to make some PvP chars and decide to fully complete NG (killing all NPC's, gettin all items/armor) and get into NG+. I killed all optional bosses and am about to kill Gwyn and go into Ng+ but I am beginning to have doubts in my Strength build.

I am running BKGA and sure it does a lot of damage but it attacks quite slow and is really heavy which makes you rather limited with what armor you can use. Maybe I need to try out some other options that still do good damage but are a bit faster, but I feel like all the good strength weapons swing at Zweihander speed.

It seems like in PvE going something like a +15 BSS would do more overall damage. Sure it doesn't hit as hard but its so fast and has such a good move set that if you threw a buff onto it then it would have much higher damage output than any strength weapon.

I am already at 25 dex to be able to use the BKGA so I could just begin to put points into dex and get there relatively quickly, but all those points in strength would be wasted where they could rather go into faith for buffs or int for damage spells.

Since I am trying to choose a character that I will attempt to take as far into the game and level up as high as possible, I really want to make sure I make the right decision. So any input from you guys as to Str vs Dex weapons and which you think are better and why would really help me get to my decision.

On new game? Strength. Strength all the way. Stun everything, one shot tons of enemies. Make yourself tanky, get a good shield. I find that strength is the way to go in PvE, at least for me. Mid-roll can dodge every attack easily, and with enough strength and a good shield you can block everything without needing to roll. Hell, you can dodge every boss attack with Fat Roll(Perhaps not Sifs circular double swing though) though should try for mid-roll. I also suggest using someone other then the BKGA for a strength build, and if you want to use a faster strength weapon there is the Man-Serpent sword, the Mace, the Butcher Knife, and I believe that the Dark Sword leans towards the strength side, though don't quote me on that. And if you buff a strength weapon, you will be getting a lot of one hits. A lot. The only place I find where dex triumphs is some boss fights, as there are bosses with attacks and dodges that are faster then you can swing your Greataxe or something of that sort(Like Artorias, Sanctuary Guardian, and Gwyn).

The sad part though, is that if you are going into NG+ and beyond, dex might be better. You just can't tank hits during NG+5 or 7, and you are going to be one-shotting a lot less things. But by then, you can switch between them easily enough.

SirArchmage has a good explenation. The only thing I can maybe add is: if you're a careful person, you can always go for a stealthy approach. Using the Fog and Slumbering Dragoncrest Ring hardly gets you into trouble unless you're careless. Using a crossbow might help. It fires faster right away, but it still needs to reload after. The Composite bow is really fast and it should scale with STR more. So that's always an option. If you're really far away, you can use Pharis bow. Just poison them from a very long distance, and they won't even react to being hit. Then all you have to do is await their death. 

I'm not a serialkiller, I swear!

Don't forget that stagger rules apply to any NG iteration though, so things like interrupting smough before he actually attacks via a heavy-hitting R2 will always work, but on NG+ and beyond you better make sure you connect.

So I decided to stick with strength and go with the Large Club. Just proceeded into NG+ and am loving it. I am going to begin putting points into faith so I am able to use Darkmoon Blade Buff on it.

Thanks for all the info.