Frankly I like Avenger way better for sound design. The Arp, envelopes and LFOs are similarly flexible but way quicker and easier to use. The drag and drop modulation system is far simpler to use, and again, similar in flexibility (probably more flexible). There are some differences in the FX department, but neither is really better or worse IMO. Omnisphere does have some really cool unusual FX though. Avenger has more bread and butter stuff, but really well done.
Where Omnisphere shines is the library. I use Omnisphere when I don't feel like making a sound. Vengeance makes great stuff but I prefer the quirkiness of Omnisphere's sounds to the EDM focused palette presented by Avenger's factory lib.
Yes, I agree, especially with regard to the effects section of Omnisphere (although the reverb modules are one of the poorest I've seen on a synthesizer).
Instead, Avenger is new and it is only a matter of time before there is a wider range of sounds for this beast.