Learn Spanish (Latin America): A pesar de que somos un gran elenco, necesitamos practicar. - Even though we are a great cast, we need to practice.

The adjective grande changes its meaning depending on where it is placed. When placed before a singular noun, it shortens to gran and means great, excellent, or fantastic (a great cast). If it were placed after the noun (un elenco grande), it would mean a physically large cast with many actors.

What does a pesar de que mean, and could I just use aunque?

A pesar de que translates to even though or in spite of the fact that. You can definitely use aunque here (Aunque somos un gran elenco...) to mean the exact same thing. A pesar de que simply places a bit more emphasis on the contrast between the two ideas.

Why does a pesar de que use the indicative verb somos instead of the subjunctive here?

You use the indicative (somos) after expressions like a pesar de que or aunque when you are declaring a known, established fact. The speaker is confirming that they really are a great cast. If they were talking about a hypothetical situation or information that isn't confirmed yet, they would use the subjunctive (seamos).

Why is there no preposition between necesitamos and practicar?