Losing original resolution unlimited backup sucks, but that's not a lack of continued focus with the Pixels, and certainly not indicative of a shift towards the 'a' series. No other phone has ever offered that functionality, and it's an opportunity cost Google figured they could recapture.
Battery life is only a failure relative to the huge leaps others have made in 2019 where Google stayed stagnant (and regressed a bit with the 4). Expect that to be a high focus priority with the 5, though not necessarily with an effort towards leapfrogging others. They just need to get to sufficient use for average users to make it through what is - for them - a heavy day on the base model
Google likely figured that, with their certainly knowing Samsung was going to introduce a high-end chromebook, there was no sense in fighting over what is at the 4 digit range an incredibly small market, so they went after the mid-segment with the Pixelbook Go.
Anyone still sporting a Pixel 2/2XL or 3/3XL is still in mighty fine shape for doing pretty much anything one needs to do on a phone today. No real point in upgrading beyond necessity until 5g lands in a device and functionally in a network.