The TimesOnline has a story, Pope set to bring back Latin Mass in face of opposition which makes a number of statements. One is that the Pope will issue the Motu Proprio despite opposition.
The author states that "the document had been expected earlier but is understood to have been delayed after a seven-page document of objections by German bishops was sent to the Pope."
That's certainly a possibility, but one really doesn't know for certain.
More interesting are some of the claims made in the piece, such as, "when the permission is published, it is thought likely to exclude prayer for the conversion of the Jews."
This seems highly unlikely. I can't imagine it will be anything but the 1962 Missal in the form as it is already used by the FSSP et al. As well, conversion, it must be stated again, is different than hate or anti-semitism. This objection to prayers for conversion is not rooted in a Christian understanding of evangelization, nor of the place of Christ in our salvation. If anything, such a concern might be addressed by explaining and clarifying such.
More to the point however is this bold bit of speculation:
"It could also include an “opt-out clause”, allowing bishops to prohibit it at a local level, which would placate both the German and the modernist French bishops."
This seems highly unlikely. It would destroy the likely purpose of the motu proprio and effectively keep the present status quo. It would make little sense for the Pope to do such, because if such were acceptable, the present situation would be sufficient, and really all that would be needed is continuing encouragement for generosity for a special permission. But evidently the Holy Father does not think the present situation satisfactory, and likely for a number of reasons.
If, as the Pope has said in a number of writings, the effective sidelining of the Roman liturgical tradition is highly problematic and undesireable, why would he set in force actions to correct that, while at the same time allowing a clause which would allow for the same side-lining to occur yet again, potentially neutralizing the entire document?
To be honest, this speculation comes off as a form of lobbying through the media, possibly on the part of those within the Church who would like for there to be such a clause, and who are therefore trying to shape things in that direction. We've seen such before.
I wouldn't get terribly excited by this speculation. It seems quite inconsistent and very unlikely.