I remember it as being the Anglo-Americal dual world power, the UK and US. The 1958 book said the power balance would shift from the UK to the US before the end, and that's happened.
What might fit better with WT ideas is to make the US the last King of the North, the last one standing in the struggle of nations... the one Michael finally has to attack.
That shift (from free South to totalitarian North) could be either: 1) pinpointed on attacking ancient holy places under false pretences and in the face of the impotent condemnation of the rest of the world; or 2) could be foreshadowed as the ultimate end of the current Middle East/Terror/Iraq/Israel situation.
Presumably, the WTS might also say that the final battle starts against radical Isalm, but ends with the JW's, who also preach for theocratic rule to replace human government by way of Holy War.
That's just my speculation on the whirrings of the WTS collective hive... it'd give real immediacy and a collective threat close to home for JW's in the West. It'd trigger all sorts of fear reactions amongst the Bro's globally (it's put them on the 'wrong side' of the War on Terror, for one thing) and it could be dragged on for as long as the War on Terror and all other Middle East issues go on for... and that could be decades.
Then they just need a couple of creative paragraphs to link the commencement of this final Act in the Drama of Nations (I think they called it somthing like that...) with asupposed commencement of 'Armageddon' in 2004, being 1914 + 90 years - one modern life span. Then they overcome most of their chronology problems too.
Max - of the frustrated Watchtower writer class