Yes Samsung is refusing to release source code for Exynos processor.
you may want to go for the GT i9505 which has a Snapdragon processor (but I don't understand why you would want to trade for a phone that has very similar specs to the One).
Source code mostly comes from Qualcomm thus more development
Sent from my GT-I9505 using XDA Premium 4 mobile app
White Samsung Galaxy S4 LTE i9505 + white S view Cover for everyday, Protective Cover+ for hiking, camping etc...
Rom: Stock non-rooted 4.4.2
SD card: 32 GB Class 10
Tablet: White iPad Mini + Green Smart cover
Firmware: iOS 7.1.1
Samsung Galaxy Tab 2 7.0 (Family tab)
ROM Stock 4.1.2