There are two questions to address here. The first is how do you tell the pastor his/her sermons aren't hitting your mark. The second is why sermons preached today seem so elementary. Let's look at them in reverse order.
For those who have been in church for nearly their whole lives it seems in the past five years or so the sermons have been getting simpler. Oh, they still contain scripture, illustrations, and applications, but the topics themselves seem to avoid the troubling passages and some of the deeper theological issues. The question is, "Why?"
For those of the "Builder" and "Senior" generations (those born prior to 1945) this trend may be quite troubling. However, our world has changed significantly. Prior to the '60s there was a predominant world-view in America that the U.S. was a "Christian" nation and the vast majority of people were practicing Christians. Churches sent missionaries to foreign countries and the mission at home was to build strong nuclear families by supporting the work ethic, supporting the government (that reflected the "Christian" views of its constituents), and confronting un-Christian attitudes and practices in society. It was assumed Christianity, as taught in the church, was practiced and supported at home.
Enter the '60s. The "Baby Boomers" (born form 1946-1964) lived through Vietnam, the assassination of a president, and Watergate. Suddenly they couldn't support their government. The Seniors and Builders weren't able to understand this distrust and saw the younger generation as rebelling. In general the churches reflected the Seniors' and Builders' viewpoint and addressed the issue by continuing to preach support for nuclear families, the government, and confronting this rebellion as un-Christian in attitude and practice. In doing so the church lost most of a generation.
The world today is not the same as the world prior to the '60s. Less than 50% claim to be practicing Christians. The stories, theologies, and traditions of the church are generally unknown to those born after 1946; indeed, many from this generation have never been to church for more than a funeral or a wedding. However, though organized religion has lost many of these, a vast majority have been, and continue to be, interested in spirituality.
Enter the church. The church began to realize that it had failed to minister to a whole generation and had lost them. In the past ten years there has been a mad scramble to figure out what went wrong and attempts made to correct the situation. Some Boomers began visiting churches to see whether there was a spiritual answer there. And younger generations have also cautiously looked again to the church with some of their spiritual questions. But these folk don't know anything about church, or about Christianity–except what they see on TV, and that's not very flattering. So pastors have been going back to the basics with sermons relevant to those returning to church. (Let's face it, there are a lot of people who think Joan of Ark is Noah's husband and Easter is a celebration of a bunny named Peter. And someone has to change that.)
So that's why sermons have been simplified over the past several years.
But how do you tell your pastor you're not getting much out of his/her sermons? The best way is to make an appointment with the pastor to visit the office and share your concerns. And then listen. Your pastor may well be trying to reach those potential visitors. And if your pastor is like me, s/he'll be pleased to know you're listening and are interested in a deeper spirituality. In fact, they may have some suggestions to help you find the deeper truths in the sermons being preached. Listen and practice what they preach. And most of all, love your pastor. They're doing a tough job in a nation that doesn't understand anymore. Criticize gently and listen carefully. That's the key to sharing your concerns.