... since it has been quite some time that no new version of the QT wallet has been mentioned, neither some innovation to keep it going for the long term.
As long as it works fine, it doesn't need "innovation". Don't get fooled by the "we need innovation"-hype.
It would become ideal for Dogecoin to add SegWit to its code, and gain traction if it gains acceptance from the miners.
SegWit is only needed to work around the small blocks in Bitcoin. Doge is much faster, and making a transaction is about 25,000 times cheaper than Bitcoin. There is absolutely no need for the hassle of SegWit.
Nevertheless, Dogecoin is a great cryptocurrency being inexpensive and relatively stable, making it a great way to tip others or send micropayments faster than BTC at a fraction of the cost.
I've always liked Doge for this. It's quite stable in dollar, the Bitcoin-value varies wildly caused by the fluctuations in Bitcoin's own value.
What I don't like much about it, is how it's mined: it quickly produced 100 billion coins, and now continues to produce 5+ billion per year. See
https://dogechain.info/statistics for a graph.
It's designed for inflation, but that might also be what keeps fees low.