The average Greatsword (+10) does 400 base physical damage and scales very good with strength (A).

I modified it to Lightning Greatsword +10, scaling with both strength and faith. It does about 660 total damage, 330 physical and 330 lightning damage. Stat at 50 for both strength and faith.

Not sure how Drangleic sword is compared though.

for me moveset > damage, unless it's the difference between one shotting and two shotting an enemy, damage means nothing, if you still have to kill an enemy with 2 hits anyway, what does it matter how much damage you would do with a single hit ? Claymore has one of the best movesets in the game, especially two handed attacks, R2 has a spear level of reach and R1 is still the trusty horizontal swing, which is alot better than the new vertical slash imo.

also the in game Greatsword is not a greatsowrd class weapon, it's an ultra greatsword, so naturally it will do way more damage than greatswords.

I'm not a fan of the ultra great swords, there too big, heavy and slow, they do a good amount of damage but I always find I slaughtered when fighting a dark phantom who has the normal greatsword weapons simply because they swing faster and take less stamina too do so.

I'll stick to the drangleic+5 as it seems to be the best for me. I think the one sword that could be better is the mirrah greatsword because although it's max upgraded physical is 250 it has a bonus parameter of 'A' for dexterity and 'C' for strength while the drangleic is B for DEX

Get a Mastodon Greatsword, infuse it with Lightning, upgrade it to +10 = Best Greatsword in the game. 

At Lightning +10 it has 210 Phy/210 Lightning dmg, plus B scaling for Str, E for Dex and B for Faith (Since Lightning damage now scales with Faith). It easily goes near the 600 dmg mark, it's awesome for main game and NG+ and pretty useful for PvP.

Also, it's infusable with Sunlight Blade as well, if you opt to invest some points in Faith, so add an extra 50 Light base damage +30% increased Light damage.

Fixed

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I never knew that Mastodon Greatsword maintaints the ( B ) scaling even after infusion with an element. Got to try it ^^ . Eventhough I doubt that I'll ever replace my currentely favorite Lightning Zweihander.

Actually that's not true for Dark Souls 2 anymore. Flame does scale with both Int and Faith now. While you get bigger gains overall by just increasing your pyro flame, a character with a 30/30 spread of Int/Fth has the BNS advantage over a character having a regular 8/8 Int/Fth spread, both with ascended pyro flames +5.

Same holds for weapons as well.

Just out of interest, I've just got to DRAGONS SHRINE, how much longer would you say I have before completion?

Took 75 hours but finally completed it, now preparing for new game plus :)
Thinking about using ascetic on Dragon Aerie to get more Ores :)

how long is a peice of string for that one, i think 3 more required bosses from that point, but i spent alot of time doing more of the optional stuff as well once i got there. 

Think it can be done in 1 play through with bonfire ascetic and some imense PvP Grinding