I have bought a 2.5 in February and I highly doubt they will bring another update in the next few years. From their older wheels to csw 1,2 and 2.5 they got closer to the professional level every time.
Now they basically got to this level with the DD wheels.
The v2.5 has no downsides apart from not being a DD wheel.
Csw 1 to 2 was a massive power increase that was needed to simulate stronger cars. V2 to v2.5 was optimising, polishing and introducing the updateable motor software.
So I don't see any reason why a v3 should come at all. Apart from... Offering something new but there's no real thing to change. It sits right below the DD wheels on the market and above anything else out there.
But I know fanatec doesn't always go for the most logical thoughts so who knows