It's long been said that the hardest thing to do is to make something simple. And that's likely true--the easiest things we use today are insanely complicated and complex behind the scenes. It's a good lesson for marketers as well.
There's always one more feature to throw into the launch; there's always one more benefit that some random customer got one time that has stuck with you; and there's always a c-level executive who wants to throw their $0.02 into the mix.
But here's the thing. Your audience can only understand so much and take in a few things--they won't remember the 4th or 5th thing that your product does--you'll be lucky if they remember the 1st or 2nd. So focus on the critical few things that make your product or service different. Stick to your guns and make sure the key points come out--and then cut.
It will be easier to market, it will be easier to focus on what matters to your customer, and it will be easier to articulate when you have 30 seconds to pitch it.