Make the side to which a decoupler remains attached toggleable.

[BlueCanary]

At the moment when a decoupler is staged it detaches from the part it was placed on and remains attached to the parts placed on it. For the most part this is fine, but there are situations where it can be a real pain in the neck, for example:

 - Releasing air-launched craft (eg. X-15 or Spaceship One style craft): you end up with a draggy, wierd looking decoupler stuck on the craft you release, when in reality the decoupler would remain attached to the carrier plane.

 - When using hardpoints to attach weapons or drop tanks to a military plane, the hardpoint stays on on the weapon, completely screwing up it's flight characteristics and making it impossible to reload anything on the hardpoint if you're using KIS/KAS.

There are probably a lot more situations where having the option to choose which side of a decoupler detaches would help, but those were the ones that sprang to mind.

A simple tweakable option to choose which side a decoupler detaches from could solve a lot of design headaches, and (although I have zero KSP modding experience) I'd imagine it'd be quite a simple change to make.

 

EDIT: Sorry, forgot to say I'm talking about radial decouplers.

Edited December 19, 2015 by BlueCanary

[Tex_NL]

For the sake of argument I'll assume you're talking about radial decouplers. In case you were thinking about in-line decouplers the answer is easy, just flip them around.
A toggle option for radial decouplers would be very beneficial but the ability to flip them around would be the absolute ideal option.

In the mean time I do have a workaround for your issue. It's a dirty fix but it does work.
Build your craft as usual, with the decouplers facing the 'wrong' way. Now change the root part to the booster/weapon you want to decouple. Take the 'carrier' and decoupler off and put it all back together again. Change the root part back to the original place. Now your decoupler is facing the other way.
For air launched craft it can be even easier: Start your build with the air launched craft. e.g. Make that craft the root, not the carrier.

[GluttonyReaper]

On a related note, I would quite like some kind of radial ... separator? Something which detaches from both sides, and ca discarded as debris after use. Would be quite nice for little probes.

[pandaman]

Don't they have arrows which point towards to bit that flies off anyway?

I'm not sure about having them togglable in flight, but in the editors would be useful especially for when you want to reconfigure an existing craft. 

[Xavven]

You can also make your own "radial" decouplers with cubic octagonal struts and regular decouplers, or a stack separator.

[Tex_NL]

1 hour ago, pandaman said:

Don't they have arrows which point towards to bit that flies off anyway?

I'm not sure about having them togglable in flight, but in the editors would be useful especially for when you want to reconfigure an existing craft. 

Yes they have. Those are the in-line decouplers. And as I stated earlier if BlueCanary was talking about those he could simply flip them.
Radial decouplers however do not have this same luxury, they can not be flipped. And these are the decouplers BlueCanary is talking about.

[pandaman]

18 hours ago, Tex_NL said:

Yes they have. Those are the in-line decouplers. And as I stated earlier if BlueCanary was talking about those he could simply flip them.
Radial decouplers however do not have this same luxury, they can not be flipped. And these are the decouplers BlueCanary is talking about.

Ah yes...   I missed that bit...

A way to 'flip' the inline decouplers in the editors could be a handy though. 

I get what the OP is saying about the left over bits of radial decouplers leaving funny looking lugs too, and yes as the OP suggested, a 'flip' option could be useful anyway, and not just for aesthetics.

I'm not near my PC just now so can't check, but don't the pylon type attachment points behave like the OP wants, in that the load falls off and the pylon stays on the vessel?