Yeah, while I have some paddle holsters, I would never use them for EDC, as they just are not secure enough in many cases, and do not pull the firearm in close enough to the body for concealment.
I think it is telling that even Springfield's own store does not offer any type of OWB holster for the XDE. It is apparently assumed you will be wearing the XDE IWB. I've got Springfield's paddle holster for my XDM's, but would never use it for concealment - maybe for USPSA shooting, but more likely to use my Crossbreed Snapslide for that.
Be sure when you receive your new XDE, to go online and register with Springfield. They will give you a ONE TIME offer to buy all the accessories you want for half price. That is how I got most of the magazines and such for my XDM's.
One POSSIBLE option is this holster from Desantis:
Shop DeSantis GunHide for premium leather and kydex holsters, duty gear, and more. Experience family-owned, American-made quality. Find your perfect fit today.
www.desantisholster.com
While they only let you select the XDE in 3.3", if the holster is not closed, and it does not appear to be, then it will work with the 4" barrel. I use the same holsters for my XDM 3.8" and 5.25" - the 5.25" just hangs out a lot more on the bottom. This holster appears to clip over the belt, rather than require you to thread your belt through it. I like the Desantis holsters I've had.