As far as 23" bass drums go, one more item or option in our arsenal isn't really a bad thing. While it's possible (even likely) that DW is blowing smoke about the advantages of a 23" bass, the flip side is that there are people who can tell the difference, and DW is willing to accommodate them. That's a damn sight better than I can say for some other drum makers. As to the 15" tom, I have heard much wailing and gnashing of teeth about how "odd" sizes are a pain in the arse, and nobody likes them. Well, I'm not nobody kids, and I think that 13" and 15" toms are perfectly useful as long as you know how to apply them. having a 12, 13, 14, 15, 16" tom setup is a mostly unlikely scenario, whereas a 10, 13, 16" or 12, 15, 18 is much more apt to happen, so let's not be down on the odd sizes. It's also regrettable that these odd sizes are falling out of fashion, and most drum companies will only offer the 15" drums in their premium lines. I've said it before; there is NOTHING wrong with 6", 13" or 15" drums. NOTHING!! EVER!!!!
Have a nice day!