"We all know of Packer's ecumenicalism, but I have yet to see evidence that he embraces anything other than the doctrines of grace."
I would offer the following in response to the first part of your statement, ie "We all know of Mr. Packers ecumenism":
Are we not explicitly told to: "Come out from among them and be ye separate and touch not the unclean thing."? Is not Rome an "unclean thing"? Can ecumenism, including an embracing of Rome, tacitly or otherwise, not to mention other heretical sects, be considered to be "coming out from among them"?
And are we not also explicity instructed; "Ye adulterers and adulteresses, know ye not that the friendship of the world is enmity with God? Whosoever therefore will be a friend of the world is the enemy of God." ?(Jms 4:4) Is not the church of Rome part of the world and a tool of the "ruler of this world"?
These are not difficult questions to answer for even the weakest and least educated of the Lord's sheep. How therefore does Mr. Packer find difficulty in responding Biblically, for surely, on some level, as for example in his natural judgement as opposed to his spiritual judgement, he sees the error of his actions? I would suggest that the answer is found in the last quoted scripture, namely, that Mr. Packer "would be a friend of he World".
In response to the second part of your statement, ie; "but I have yet to see evidence that he embraces anything other than the doctrines of grace."
It would be accurate, in my opinion, to say that Mr. Packer esposes the doctrines of grace, or that perhaps he gives lip service to them, but to say that he embraces them, and that there is no evidence that he embraces anything else would make your statement in it's entirety a contradiction, because he has admitedly embraced ecumenism and the world. One cannot embrace the world, ecumenism, Romanism and the doctrines of grace at the same time, for to embrace the doctrines of grace is to reject Rome and ecumenism and any and all but adherance to the true Gospel.
One cannot truly embrace the doctrines of Grace and "be a friend of the world". One cannot love Christ and the world, just as one "cannot love God and mammon".
Or, again, the Lord asked the point blank question of the Pharisees; " How can ye believe, which receive honor one of another, and seek not the honor that cometh from God only?" Jn 5:44
I interpret the Lords words to imply that as long as the Pharisee's, or Mr. Packer, or you, or I, seeks the approval of the world over the approval of God, we cannot savingly believe, and one of the most obvious evidences of where we stand is not the words we speak to the contrary, for the Pharisees were full of words of devotion to God rather than the world and Ceasar, but rather, the actions we take, "to come out from among them and be ye separate".