It seems unarguable that the European Commission really doesn't want Britain to be a part of it - that's the only conclusion one can draw from its threat to sue the UK if we don't weaken the eligibility criteria for benefits. In one sense it's completely understandable - the European ideal (and policy) is for laws and benefits to apply equally to all EU citizens in any given country, so if you give this policy any credence then you must press for the British benefit rules to be amended.
In another sense, it's utterly demented. The Commission (an unelected body) is part of the Eurostate which is deeply unpopular in the UK; if you want evidence then see this week's Question Time from Liverpool. It's gifting headlines to any Eurosceptic UK newspaper, which is really all of them save the Guardian and Independent. Its timing is impeccable; when government cuts are pressuring budgets UK-wide it's threatening another £2.5bn+ spend on non-UK citizens. If it was trying to provide the UK government and Eurosceptic MPs with ammunition to argue against providing any more financial aid to the EU, it could hardly have done better.
Having met a COREPER member some years ago, I would lean towards the theory that the Commission genuinely do not understand the political implications of what they are demanding - they appear wrapped in their own little Eurocentric world with only a hazy notion of the concepts and implications of national sovereignty. What I don't think they realise is that in this approach they are only accelerating the inevitable demise of the Euro, and may eventually contribute to a substantial fracturing and simplifying of the Eurozone itself.