No, there won't be any significant problems if you omit vanilla essence from a cake recipe. Vanilla essence or extract is commonly used in baking to add flavor and aroma to cakes, cookies, and other desserts. However, it is not a critical ingredient that affects the basic structure or texture of the cake.
If you decide not to use vanilla essence, the cake will still bake and turn out fine. The absence of vanilla will not prevent the cake from rising, and it will likely retain most of its expected texture and consistency. The cake might have a slightly different flavor profile without the vanilla, but it will still be enjoyable.
If you're omitting vanilla essence because you don't have any on hand or if you prefer not to use it for personal reasons, you can consider using alternative flavorings. For example, you could use almond extract, citrus zest, or other extracts like lemon, orange, or almond to add a different flavor to the cake.
Keep in mind that some recipes might be specifically designed with vanilla flavor in mind, and omitting it could alter the intended taste. However, in most cases, skipping the vanilla essence won't lead to any significant problems or baking disasters. Feel free to experiment and adjust the recipe to your taste preferences.