The sand should be removed regardless of whether you're breeding your dragons. And this isn't me "beating you up" over the topic, it's me trying to save you a lot of money, time, and heartache, as loose substrates in general are not only dangerous to Dragons, but they are totally unnatural...The Australian Deserts they come from contain little to no sand at all, they are hard, rocky terrain with vegetation, so why would you want to make your Dragon live in a totally unnatural environment, regardless of the health issues they cause? Also, everyone thinks of Bowel Impactions as the main issue with loose substrates because Dragons lick everything, and while this is a huge issue, it's not the main risk you are presenting to your dragons by keeping them on sand...It's the fact that Dragons are so very prone to chronic Upper Respiratory Infections, Skin/Scale Infections, and Eye Infections when they live on loose substrates, as they harbor and breed all microbes including bacteria, fungi, parasite, protozoa, etc. So the bottom line with that is that it's just a totally unnecessary risk that you are putting your dragons in the middle of.
As far as it being a barrier to them breeding, if you have to ask that question, that tells me that you are not prepared to breed them in the first place. Sorry, not trying to be rude or condescending, but it's the truth. There are already literally thousands of baby, juvenile, and adult Bearded Dragons of all morphs and colors all over Craigslist and other sites, in every state, every town, because people think it's a good idea to breed their dragons. Unless you already have homes for potentially 30 babies per clutch, times 2-3 clutches per mating, so potentially 90 baby dragons from one breeding session, then beware.