Some features to consider that I have learned I like on my bench.
1. Build twice the shelves you think you need. More gear than you think will accumulate over time.
2. A perfectly level shelf at eye level. Dedicated full time for your scale and trickler that is right next to the powder measure.
3. A quarter inch lip all the way around the work surface that keeps all spilled powder on the bench.
4. A power strip bolted to the bench.
5. Machinists lamp that is articulated so you have light where you want it.
I cannot argue with any of this.
I failed to mention, the area where your press will be, needs to be nearly as strong as an anvil. I'm sure you know, sizing brass requires some serious force from time to time.
2"X4" table frame will be fine, provided the field is not too large. Mine is 3' deep and 8' long, thus the 2"X6" frame.
And being a welder first, and carpenter second, I don't use nails too much. Glued and screwed is my motto attaching wood together.