ok so let's think things through here: Bay's take on the franchise specifically emphasizes how, in addition to being a sort of sinister disguise, transformation literalizes the connection between a symbol and its ideological content. most Autobots are cars, and we're told over and over again that cars represent freedom, consumerism, luxury, the archetypical American teenagehood, etc, all of which are values the movies' so-called heroes align themselves with (until the CIA gets second thoughts in AGE OF EXTINCTION). so a lion's alt mode would obviously be adjacent to monarchy, maybe a warship named after a monarch or a specific fancy car used by one, since that's what lions are all about in our cultural imagination