Also interestingly, the article above specifically mentions the passport tactic being used in the other notorious breakaway republics of Abhkazia and South Ossetia.
In fairness, if the rest of the world accepted passports of Transnistria, Abkhazia and South Ossetia, there would be considerably less justification for Russia providing them Russian citizenship, though Transnistrians don't have any difficulty obtaining Moldovan passports if they want them. (Russia had a pretext for granting Russian passports to Crimeans too, since a right of dual citizenship was established in Ukraine's short-lived original constitutional arrangement with the region.)
Russia has never particularly disguised its belief that Crimea is an integral, historical and important part of its territory, whereas any limited value Transnistria has to Russia probably involves the Russian presence there remaining in a supportive, "peacekeeping" role as a symbol of Russia's reliability as an ally. That said, it notably hasn't formally recognised Transnistrian statehood, and is well aware most Transnistrians would welcome annexation (they had a referendum) if it could be achieved peacefully.
(I'm only bringing this up because I think it's interesting, not to dispute anything you've written)
The Russian move into Ukraine seems to have some medium-to-long term planning behind it.
For example, there were reports back in 2008 of Russia handing out passports to residents of Crimea:
http://www.telegraph.co.uk/news/worldnews/europe/ukraine/257...
Also interestingly, the article above specifically mentions the passport tactic being used in the other notorious breakaway republics of Abhkazia and South Ossetia.