The thing I hate the most about my system: No damn remote and no decent preamp options under $1k. I'm buying an Oppo BDP-105D when I can afford it and plan to use that as my preamp. I think the Oppo product line is an amazing bargain for what it offers, but if Schiit could over the same audio options that the 105D offers without the disc drive and the video components, I'd be totally fine using my Bifrost and PS4 with said preamp. I've considered Emotiva's preamp, but I don't want to spend that much just for a preamp when I can get the 105D for just a few hundred more. It doesn't make sense to me that there isn't a good preamp out there under $600 or so that can do what I need, which is just remote volume control and a few RCA outputs. I think an Uber version with a phone app that controlled music from my computer and streamed it into my Bifrost would be amazing.
DAPs: I bought a Fiio X1 for my girlfriend, a non-audiophile that often is aggravated with my audiophile obsessions, but she has really grown to love it and the high res music I've bought for her (all 24/96 FLAC). She looooves hearing new things she had never heard before in the music and has had the same joy rediscovering her old favorites as I did when I bought my first Modi. I think there is a serious market out there for DAPs, but people really need something to convince them, because the Pono certainly didn't. As Jason said, a phone and decent headphones is all most people need. For me, a good DAP adds a lot over Spotify over a phone and I think Schiit would be able to convince people of it with their expertise in marketing and USA made products. Fiio makes great stuff, but their crappy English isn't really a good excuse for marketing.
Portable DAC: I have an E18 and I love it. The only thing I don't like is how crappy the OTG cable is. Both of mine failed within a year. I'd love to see a good OTG cable at least, or some kind of cradle type connection, I don't know. All I know is the thing I hate the most about my E18 is how hard it is to keep it connected to something in my pocket or on a plane. In the car it isn't so bad, but walking around with it can be a pain.
Two Channel: I don't know how you're going to beat Emotiva and Outlaw here. Their amps are pretty awesome. I got nothing here.