I mailed them about that a week ago (even with photos from Endomondo and Runtastic running on my SW2) and got this answer:
Originally Posted by Endomondo Support
Thanks for your email.
At the moment, we don't have any plans for a new smart watch integration. I'm sorry.
Google Nexus 5: Android 4.4.4, KTU84P [ART]
Google Nexus 10: Android 4.4.4, KTU84P [Dalvik]
SE Xperia X10 mini: Android 4.1.2, MiniCM10-4.1.0-20130518-NIGHTLY (JZO54K)
Accessories: Jabra Rox, Sony SmartWatch 2 SW2