The ecumenical movement has been a disaster for the Catholic Church from top to bottom. Instead of following what was prescribed at the Second Vatican Council, clerics sought to achieve false unity by pretending divisions don't exist, a kind of "ecumenism without conversion." Many place the blame at the feet of the hierarchy, and while there is much blame there, the sad truth is that the entire affair was a fool's errand from the very beginning.
Unity the way most in the ecumenical movement see it is impossible because of the nature of protestantism itself. Protestantism is a house divided, and one that is constantly dividing.
Homosexuality is an outstanding example of this. The protestant world is ripping itself apart over how to deal with same-sex marriage. Liberal groups like the Episcopalians have practically embraced it. Baptists and Pentecostals, on the other hand, are dead set against it. The Anglican Communion is almost at the point of schism, with conservative African and Third-World churches condemning it while many American and European churches actually practice same-sex marriage.
So what will it be? No matter what the Church does with regard to homosexual acts (and She can only do one thing: condemn them), massive numbers of Protestants will be outraged at the decision. The result is that ecumenical groups do nothing, crippled with fear that one sect or the other might break the illusion of unity.
The ecumenical movement has taught us only one thing: Preach the truth. There is no way to please everyone, and armed with that knowledge, the only sane solution is to forge ahead and boldly proclaim the Gospel, come what may. Protestants and Catholics are not united, and they will only be united when all are converted. To convert, they must be told they are wrong, and that the Catholic Church is right — a mortal sin in the eyes of the ecumenical movement.
Until then, the only thing Protestants will agree on is that the Catholic Church is not the True Church established by Christ.