for defender, blast+flare or explosive+flare?

Title. I think explosive does slightly more damage and splash damage, but it takes longer to recharge than blast and you need to lead your shot a lot more.

 

I go with flare + ExC. My 3rd weapon is the standard cannon so i can still do something while waiting for the ExC to recharge. Basically, I have 1 high dps and 1 burst weapon to combo with the flare

 

I run flare plus EC. For a third I run big torpedo, or 2nd explosive cannon.

 

Personally, I'd go for the XCannon instead of the blast. I don't know what level your Def is, but at high level it has 3 weapon slots for a total of 5 slot-points. So a BC would be like wasting a slot point, unless it is the only 1-pt weapon you bring with you.
Yes, XC has a longer cooldown, but I find that CD isn't as important as it is often made to be. Basically, CD only makes a difference *if and when* you spend a long and uninterrupted period of time shooting at someone. But in general that doesn't/shouldn't represent a large share of a battle because by definition, it means the other player(s) can fire back at you. Typically, the game is played more like : you take one shot, then take cover, then take another shot with another weapon, and so on. That gives long CD weapons more time to recharge, which reduces the importance of CD.
Now, because CD can be important from time to time, I carry a standard cannon (with a couple of fire perks), plus an XCannon (1 fire perk). A flare gun would fit well here as 3rd weapon, obviously, and I sometimes equip one (for guild quests), but I usually take a grenade. With the fire damage (and %fire perks), it gives you the ignition source you need AND it can pack a heck of a punch (mine does about 2000 dmg in total when I aim well). The damage is much better and faster than the FG.

 

I run EC, Reg. Cannon, and Sniper but there are times I will switch out a fast torp or a flare for my sniper.

As the person above said, the EC paired with a standard cannon works because of the under 4 second refresh of the standard cannon.

 

Since were talking about defender load outs here, what do you defender mains think of the Gatling gun as a support weapon on a defender? I see a lot of defenders running flare/ExC/cannon (although I don't see a lot of defenders in general) but I'm thinking that flare/ExC/GG might be a more efficient combo

 

I don't have a gatling gun to really see the difference it can give. My thoughts only for the gg is its accuracy and does not have burning combo unless you have the event perk before.