Newly launched casinos differ a lot from each other. Some have an original approach and get it right from the get go. However, sometimes the product isn't 100% finished at the time of the launch. Getting there may take a while, whereas older brands can already offer the experience you are looking for.
The other extreme are generic casinos that are fully functional from the start but also indistinguishable from every other site using the same casino platform. This doesn't mean they are bad casinos, just unimaginative.