You know decent projects have GUI wallets right away. Most developers are able to make them in a couple days. I never understood why Dero wanted to wait until Q2. Six months after starting the project. Maybe they are making a wallet that will blow our minds, maybe they wanted to wait until Atlantis, but who knows. Six months is a long time.
The wallet, as you said, is not in itself a big issue. However, keep in mind that our devs already rewrote everything with Atlantis, so anything that communicates with the core (such as a wallet) must be built after the core is finalized. Hence why something so simple has been pushed back so far