The Russian Emergency Measures (REM) rule does not seem to work as intended. Instead of providing Russia a robust defense of the Motherland, the REM rule can make the Tsar agnostic or even supportive of a British fleet in St. P or an Ottoman fleet in Sev. The Tsar might reason that the UK or Ottoman fleet cannot proceed further inland, so the loss does not make him vulnerable to further attack; and the loss is otherwise without material impact to his unit count because of the REM rule. Indeed, the loss could even be coordinated, perhaps to solidify the UK or the Ottomans as an ally and freely fund one of their units, which may after all be used to fight Germany or Austria as common enemies. In essence, the REM rule seems to currently provide a perverse incentive for Russia to bargain its homeland rather than defend it.
This could be fixed fairly simply by adding a time limit on the REM rule. If one of Russia's home builds gets taken, the REM rule should take effect as it currently does, but if Russia does not regain the home build within a set time period (1 or 1.5 years?), the REM rule should lapse. Russia would then lose the unit as it ordinarily would without the REM rule. The time limit would define the REM rule's additional unit as a use-it-or-lose-it opportunity for Russia focused on homeland defense.