‘The only true ecumenism, between East and West’
Basically yes but while unity talks between infallible and fallible churches are a waste of time, the difference between Rome and the Eastern communions, the biggest of the latter being the Orthodox, is just as intractable, an inch wide but miles deep: the scope of the Pope, not to be confused with Protestant and Modernist frustration with the Pope for being Catholic (‘I can’t change that even if I wanted to. I’m only the Pope.’). So one can do charitable work with mainline Protestants (privately send aid to disaster areas, work to get the troops out of Iraq, defend immigrants and Palestinians, etc.), and charitable work plus culture-wars coalitions (anti-abortion being the big one IMO consistent with individual liberty) among Roman Catholics, Orthodox and conservative Protestants (two apostolic groups and all three arguably worshipping the same Christian God, less true in practice of mainliners, who are now more like their Unitarian cousins), but unity is one side surrendering. One side would stop being what it is. Roman Catholics become big Western Rite Orthodox or the Orthodox become, at best and as Rome wants, liturgically unchanged super-Greek Catholics. Chances are neither will happen. (The mainliners want the trappings of validation from the ancient churches while turning those churches into changeable denominations, effectively abolishing them.) Once each side has taught its position to the other (the actual value of ecumenism, which along with classical liberalism means the sides stop trying to kill each other) then it’s like Patriarch Jeremias and the Tübingen Lutherans: let’s stop wasting each other’s time and talk only for friendship’s sake. Or the hardliners have a point but you don’t have to be a jerk about it (for example online Orthodoxy’s ‘self-loathing converts’ mining the most obnoxious anti-‘Latin’ old-country polemics they can find). That and, as this entry says, Western Catholicism and the East sharing churches (I understand a Russian Orthodox group from the Ukraine recently had Liturgy [Mass] at St Mary Major in Rome), problematic from a one-true-church perspective but understandable in that Rome gives born Orthodox the benefit of the doubt (not Protestants but estranged Catholics).

BTW Orthodox doctrine on paper (Trinity, hypostatic union, Mother of God and icons – nothing else was challenged so nothing else was defined) is Catholicism circa 1000.

And the Russians should shut up about ‘Uniatism’. 20 years ago the western Ukrainians took back the churches the Communists stole from them and gave to the Orthodox. Fair. (Restitution for a crime > one-true-church claim here, or the end doesn’t justify the means.) Get over it.