Crimea

Back in 18th century Ottomans directly ruled cities on the south-east coast of the Crimean Peninsula, those that are south of Crimean Mountains.

The only city north of these mountains was Bakhchisaray from which Crimean Tatars terrorized the whole steppe east of Dnipro. On some maps these areas are shown as part of Crimean Khanate, however in reality back then steppes were free and did not belong to anyone.

When Russia took over in 19th century, the term Crimea was used exclusively for the peninsula itself. Russia begun building cities all over the peninsula that eventually dwarfed Bakhchisaray, just as the new Russophone settlers dwarfed original Tatar majority of the peninsula.

Russia had two primary uses for the peninsula.

First it was a naval base for Russian Black Sea fleet. The entire city of Sevastopol was built to host this naval base. 

Second purpose was hosting various summer palaces of Emperors and other important dignitaries of Russian court who all craved warm Crimean weather and its beaches.

During Soviet times Crimea became a resort destination for Soviet citizens, similar to Hawaii and Florida in the US.

Geographically it is very isolated from the rest of the Ukraine, it is almost an island.

I have a total population of 2 million people, that is the same as Kosovo. It also has the same kind of ethnic composition with majority of population are ethnic Russians but there is around 10% Crimea Tatars in the area as well.

10% is what is left of people of the former Crimean Khanate. They do believe that they should have claim on the peninsula and have good reasons to do so, but the reality is that they are small minority on the island.

Crimean Protectorate

While Crimea by itself will make a geographically viable country. Crimean Tatar population need some form of international protection as ethnic Russians do treat them poorly.

Also, while it is geographically viable, economically it is not. Even Russian tourists prefer Antalya and Hurghada nowadays and no one else will want to vacation there.

Thus, some form of international status for the peninsula is desirable. 

It should first become a UN or better EU protectorate or a condominium with Russian Federation.

Theoretically Russia can keep souverains over Sevastopol and its naval base there. Similar to how UK has Akrotiri and Dhekletia on Cyprus, but that is not very desirable.

Alternatively whole or mostly whole Crimea should stay in Russia where it will become a playground for Russian oligarchs who will live in palaces build by Russian elites of the old.

Crimean Tatar areas then should be given to Turkey for protection.

Island can be partition in even smaller areas, but that would be complicated.