[Quoth]

If you need an ereader now, buy one now. Only worth "waiting" for upgrades if the existing products are broken (they aren't) or some amazing new technology that's must have is absolutely real (there isn't even a rumour of such).
The Libra 2 is very good for 7" and the Sage very good for 8". The Elipsa 2 "upgrade" wasn't much compared to an Elipsa (nothing much to miss if you'd just bought an Elipsa) and the Libra 2 is of little significance as an upgrade if you'd just bought a Libra.
The last Libra models had 8 G flash and the current Libra 2 has 32 G byte. That won't matter to most.
The Libra has micro-USB and the Libra 2 has USB-C (but no extra USB features, maybe charges faster, but the micro-USB can charge that fast).

There are a couple of "hidden" interesting points to Libra > Libra2:
1) The OS and user storage on a Libra 2 is on a micro SD Card, but on Libra a soldered on chip. The adventurous risk taker can dissolve the gluey water-proofing and fit a larger capacity card. But it's already 32 G byte. Possibly earlier models had less.
2) Both models have the Sketch Pad under Beta features. Surprisingly the Libra 2 can use the Kobo Pen, which allows 2 line widths and erase via the buttons. The Sketch images are saved as svg which can be copied via USB. They can't be edited once saved and the Sketch pad exited or a new one started. Basic notetaking without conversion to text (Note that the reMarkable, Kindle Scribe and some others don't do text conversion on the device, which Sage & Elipsa do, as do some apps on Android (only devices with digitiser) and some on recent & current iPads).

The main value of an Android eink is being able to use bookstore and Library apps directly.

Edit
The Kobo Pen is using the N-Trig/Microsoft protocol. The MS top button feature isn't used or needed (that's BT for One Note) and there are MS Surface compatible pens sold without that. The Pens come in versions using AAAA (about 30c and last 6 months or more) or rechargeable (about 1/4 to 1/10th running time). Often the rechargeable cell can't be replaced.