I was in a venue this weekend that would probably seat 1,500. It was beautifully designed for acoustics--lots of soft surfaces, no parallel walls, lots of sound absorption. It also had an excellent sound system run by a skilled technician. I was there for a two day event. The first night, the band sounded bad. The drums were just too loud and had the sound engineer turned up the rest of the band to match everybody's ears would have been bleeding. The next morning I came in to find the drum riser wrapped in a drum shield. Everything sounded much better. This drummer was good in the sense that he kept good rhythm and had solid technique, but he was loud enough that despite every other element working in the favor of good sound the audience still got a muddy mess. All of this is to say that I'd focus on sound abatement first of all. Rockwool sound panels and a drum shield are a great start but electronic drums and IEMs are even better. Good luck!