I seem to recall the very first idea was to have a scenario where Kirk and Picard and the two Enterprises would actually engage in battle against each other - wisely dropped when they couldn't figure out how to get to that point. But as soon as they locked down Kirk meeting Picard as the key moment in the film then everything else had to be manouvered to make that happen.
'If the Apocalypse starts, beep me!' - Buffy Summers
'The sky's the limit.....' Jean-Luc Picard, 'All Good Things'
courtesy of Saquist