The problem is that when you insist that the one true Church is the Orthodox Church, then it seems like "unity" just becomes a euphemism for "everybody else converting to Orthodoxy." Dialog is by necessity a game of compromise on all sides and, beyond accommodations as to form like with the WRO, it's unclear how much, if at all, the Orthodox Church can really "compromise" in doctrine while still retaining this emphasis on Orthodoxy having been right all along.
I'm not anti-ecumenism, but I can understand why the Old Calendarists have their suspicions.
I think it is possible to have a meeting of minds short of unity. The goal should not be unity; it should be finding common ground - practical issues that we can stand together on, such as helping the poor, oppressed, resisting terrorism, threats to religious liberty, protecting the vulnerable in our society, the family, children, creation, etc. etc. etc.
But for me it is more than this - yet short of unity - it is about recognizing one another as fellow Christians - though we each see those in other denominations in error on many things, other Christians are worthy of our love as brothers and sisters in Christ - there is empathy there, a special bond. Think of us as a very dysfunctional, broken family. How would you treat a wayward child or relative with whom you were at odds? Blood is thicker than water.
But then I am also very big on insisting that Christians actually act like Christians in order to validate their claim to the title let alone their denomination - Christianity doesn't just come with claiming it, in the 'true Church' or not.