Roy Williams raises a great point at Mountains and Molehills.
The "molehills" he's talking about are the logo, colors, and design standards you use in your fundraising:
Customers who buy from your competitors aren't choosing your competitors because they have better logos. Your problem is something else entirely.
Customers care about things like products and procedures and policies that might affect them. They care about your offers and assurances. They care about the experience you create for them.
Design is a part of that experience, but a very, very small part.
Design matters. Terrible design that's unreadable and confusing will chase away donors and kill your revenue. But the best design in the world won't take you anywhere if your fundamental call to action is not interesting to your donors.
If someone tells you they can change everything with a new logo, color palette, or design scheme, you're talking to a designer -- not a fundraiser.