Perhaps not, although it also raises an interesting question over whether the Monarch could actually say no to any request from the PM, under our present understanding of Constitutional Monarchy. When was the last time it happened?
These questions will hopefully remain hypothetical, and in the long run I am confident that the British people, backed by the weight of tradition, can be trusted to arbitrate against anyone attempting a power-grab of the sort seen in other countries. (I'm thinking in particular of Russia, which recently saw its constitution rewritten to make Putin legally untouchable in perpetuity, and allow him to be leader in perpetuity, both of which are offensive to democratic principles.) Still, the biggest weakness of the UK Constitution is its overreliance on convention, good faith, and rule of law, all of which have at least been shaken recently.
* * * * *
Returning to the narrower topic, it's presumably inevitable that the FTPA will be repealed and the old method returned to. I'm not sure that's the best answer to the failures of the FTPA, but that's not my real problem with the proposed Bill. There is no cause for including the clause excluding Courts for review, there is no particular benefit from it, and there is no particular permanence either. I'm not even sure, if it comes to that, that it guarantees that the Courts would be excluding from ruling on the lawfulness of the Clause in question itself. Would it not be a matter of law to decide what Parliament can, or cannot, say about what the Courts can do?* They are bound by Statute Law, but, presumably, there are clear limits to what Statute Law could say or do, most notably that Parliament can't pass a law that binds its successors. Even the present draft legislation had to be considered in light of potential violations of the European Convention on Human Rights (eg, by taking away the right to regular democratic elections, which the present legislation doesn't).
*See also R (Jackson) v Attorney General, which is the first (and I think only major) suggestion that judges have a role in assessing limits to Parliamentary sovereignty.