Hi John,
Excellent question about your site. I don’t know of any services that provide stylistic feedback on websites. That would be a bit tricky to handle via algorithm like most evaluators do. Generally you could do a focus group of people who are representative of the folks in your congregation and ask them what they think.
In the last couple of years, the trend has been to very large images, they’re called heroes, at the top of important pages. Generally these are the full width of the browser window and often the full height as well. That’s a very common design trend, but it’s best implemented when there is lots of good imagery available. It can be awful if you don’t have good pictures.
If you’d like to play around with a new design, what you could do is create a new folder on your server and install WordPress there. You might name it 2016 for example. Then use the export and import screens in the WordPress tools section of your dashboard to add the content to this new site.
Then you can develop it there out of sight until it’s ready. After that, there are a few small changes to make in WordPress and on your server to swap out your current site for the new one.
Let me know if I can help,
Bill