Learn Spanish (Latin America): Ojalá hubieras compartido ese conocimiento conmigo. - I wish you had shared that knowledge with me.

The tense changes the timeframe of the wish. Ojalá hubieras compartido means 'I wish you had shared' (referring to a past event that didn't happen, expressing regret). If you said Ojalá compartieras, it would mean 'I wish you would share' (referring to a desire for the present or future).

Could I use hubieses instead of hubieras in this sentence?

Yes, Ojalá hubieses compartido is grammatically identical. However, in Latin America, the -ra endings for the imperfect subjunctive (like hubieras) are used much more frequently in everyday speech than the -se endings.

Does Ojalá strictly translate to 'I wish' in English?

Not literally. Ojalá is an invariable word (it doesn't conjugate) with Arabic roots meaning 'God willing' or 'hopefully'. When paired with the past perfect subjunctive, it expresses regret about a past impossibility, which we naturally translate as 'I wish someone had done something' in English.

I always mix up ese and eso. Why is it ese conocimiento here?