However calm and peaceful the Renaissance looked on the outside underneath all that good PR was waring city states, and assassination up the culo thats why it worked. It was known for its art and forward thinking but there was much turmoil underneath.
Here are the trends I've noticed from the AC franchise as pertaining to backdrops one: more than one city ,two: strong historical ties to real struggle in strife, three: the people that were killed actually died during that time. Under those guidelines Victorian Era doesn't hold up, a; not that bad of a place to be during that time compared to more tenuous situations in France, America, and hell even Russia, B: the government was greedy but nothing from the people in the mold of social disobedience, so were they really that mistreated C: Besides Prince Albert no one else died of consequence that you could twist so that it could look like the work of an assassin.
I see your point somewhat about the cities. But I think London would be your primary city in a Victorian setting and your character could also travel to York and Edinborough in Scotland. YOu may also visit smaller towns and villages possibly like Exeter, Whitby and New Castle.
But I think if you make London grand and ominous enough it would more than compensate as there were three cities in AC1 but only two in AC2, yet everyone agrees AC2 is much better. It is about style, presentation and depth.
Again other than De Pazzi's failed coup and subsequent mob killing (as utilized at the beginning of AC2) there was not much outward violence. There was much shady backroom dealings in the Renaissance, but it was a time of far more prosperity than Victorian Lodnon.
The claim that the squalor and ghettos of London in this period, one of the absolute worst in post-Middle Ages European history, was a "nice time to live" is covering it up a wee bit. Also saying since the people didn't protest in the streets means they had it coming is...well just
I contend that Victorian England was a worse time to live in than the Renaissance, unless you were quite wealthy, a lord or upper middle class. For the majority, it was a **** hole. And it bred a class system that gave us Jack the Ripper and what Prince Albert may or may not have been doing in this time period.
I mean the post-industrial era looks rife for this setting. Look at Dickens. Look at movies like Sweeney Todd or Dracula. You can turn this pleasant time into a trip into the real ugly underbelly of the hypocrisy that was the Victorians.
The French Revolution works, but then it is a full fledged war and mass murder. Similar to AC1, but I just would prefer the post-industrial setting.
Colonial America, again is just too small. A game set during the American Revolution would be awesome. But not Assassin's Creed as the climbing, diving, slicing hero of AC would be out of place in a world of large square patterened armies of men with muskets aiming.