Here are some alternatives depending on the context:
Formal and Academic:
* Comprehensive: This directly translates the meaning of "all bases covered" and is a strong, academic word.
* Exhaustive: This implies a thorough examination of every possible aspect.
* All aspects are addressed: This is a clear and straightforward way to convey the message.
* The analysis is complete: This emphasizes the thoroughness of the discussion.
* Every relevant point is covered: This is more specific and clarifies the scope of the coverage.
More specific and nuanced:
* The essay explores all key factors related to... (add the topic)
* The argument considers the various perspectives on... (add the topic)
* The research provides a comprehensive overview of... (add the topic)
* All relevant research is included to support the claim.
* The analysis includes both theoretical and practical considerations.
Using examples:
* Instead of "All the bases are covered," you could say, "The essay explores the historical, social, and economic factors that contributed to the rise of the Industrial Revolution."
* Or, "The argument considers the ethical, environmental, and economic implications of using artificial intelligence."
Ultimately, the best alternative depends on the specific topic of your essay and the tone you want to convey. Choose the phrase that best reflects the depth and breadth of your argument.