Google has never really focused on dual SIM devices -- I would agree that there are probably better devices out there for dual SIM function, from manufacturers who have dealt with this for longer (like Samsung).
The Fire Stick incompatibility has to do with lack of Miracast support on Pixels. I'm not sure if the decision to remove Miracast support was a business decision (to focus on Chromecast) or a technical decision.
Sorry that Pixels aren't for you -- as J Dubbs mentioned above, you just need to find one that's best for your own use case scenarios. I probably don't have to remind anyone here that I've had a great experience with my Pixels, and it keeps getting better.
