The Ukraine is quite obviously a country between two blocs - the EU and the Moscow-led CIS (although it's a kind of member of the latter).
These two blocs (or rather EU / Russian government) have each their own interest in gaining more influence on the Ukraine, more alignment by the Ukraine and more close cooperation. It's almost an old-fashioned great power struggle for some not-yet-distributed piece of the world.
The methods chosen to exert influence were different, and I have no doubt that the Russian government was more engaged and resolute in its efforts. Both blocs vied primarily for the more friendly ethnic group of the Ukraine's multi-ethnic population; ethnic Ukrainians are expected by the EU to be pro-EU and ethnic Russians are expected by Moscow to be pro-Moscow. The ethnic Ukrainians were unable to maintain a pro-EU policy in part due to domestic politics, though.
The strategical core element of both blocs was apparently the hope that a friendly Ukrainian government supported by the majority of the friendly ethnic group would be in power, limit alignment with the other bloc and move towards one's bloc.
Neither bloc seems to have contemplated a strategy which relaxes primarily the Ukraine's inner tensions or pushes for primarily prosperity in the Ukraine in the medium term.
The EU's association negotiations were apparently clumsy: The bureaucratic automatons and mostly distracted politicians did not develop a concise association treaty that the Ukraine couldn't resist, with goodies and no contentious demands. Instead, the negotiations produced a long treaty draft as if the Ukraine was some country in the midst of Europe whose intent to join the EU was out of question.
The inner tensions in the Ukraine are neither going to be solved by either an alignment with the EU nor by an alignment with Moscow. It's also unlikely that any Ukrainian government could maintain a close alignment with Russia unless the Ukrainians get rewarded for it with great prosperity (economic growth) - an outcome that's unlikely with either alignment as long as the inner tensions persists and focus cannot be directed at economic policy. A close alignment with the EU would rather increase the inner tensions.
An alternative exists; the Ukraine as a neutral buffer country between both blocs. This is runs counter to the instincts of both the Russian government (which attempts to keep the bloc's borders far away from Moscow and still remembers the old times too well) and of the EU (which is still convinced of its mission to unite Europe, which means to grow - and its bureaucracy loves growth as any bureaucracy does by design). So neither bloc seems to consider this as more than an interim reality.
A second alternative is to split the country, but a look at ethnic maps shows quickly that this isn't going to be easy or end up being satisfactory.
|Russian as mother tongue according to 2001 census, (c)Tovel|
A split would lead to Russia taking peripheral regions (mostly the Crimea) and still having the forward-most EU-aligned country (or EU member) only a few driving hours away from Moscow. Plenty self-identified Russians would then stay in a Ukrainians-dominated Ukraine, and form a likely persistent political minority which would feel oppressed and provoke further outside interferences from Moscow.
Another alternative would be to first relax the inner tensions, then see what happens alignment-wise.
Both Bruxelles and Moscow are most poor advisers for this, and obviously not very interested in this scenario.
The Swiss on the other hand might be ideal. For starters, they know how to run a multi-ethnic, multi-language country without too much turmoil.
Their plebiscites turned their actual cabinet and head of government institutions into much less important and much less contested offices than we're used from other countries. No ethnic minority would need to feel oppressed in such a state because they would not be ruled by some highly visible top politicians anyway. The contentious political debates would tend to be centred on the plebiscites instead.
It's one thing to not be on the winning side of an election or plebiscite, and it's another to see the results in shape of the other part's politicians in power on a daily basis.
I don't think a federalist approach would help here, as the Russians are too much in the minority.
A fourth scenario would be to simply turn the attention and energy towards materialistic things; an obsession with wealth might help distract from ethnic collisions. This is unlikely to happen unless a government succeeds in pushing through a great economic program, gets very favourable trade deals with both blocs and weakens the currency.
A fifth scenario would be most cynical, but was proven again and again; when two parties are in conflict, the easiest way to cool this conflict down is usually to redirect their anger on a third group. A mass immigration of Muslims or some terror by idiots not aligned with either group could 'serve' this purpose.
Obviously, I wished the EU had been deliberately smart and self-disciplined in this entire question. But it would have been even better if the Ukrainians had found a way to relax their inner tensions in the past two decades. They know what's at stake.
edit: Disclaimer about my earlier position 2008-04 Alliances and guarantees of independence
(I was against inviting them into NATO, especially while Dubya was still in office and especially as a cabinet-level decision. I sill think this should be a plebiscite-level decision.)