I think for a mid-market card then the performance is fine, and for those new to PC gaming it makes a lot of sense, especially with the bundled games. Yes if you already own a 290X/390X/RX/480/RX580 then you this isn't an upgrade, but instead of whinging about it buy a GTX 1070 Ti or a Vega 56, as you are not going to see any faster cards in this price segment any time soon.
No doubt Nvidia will do the £329-349 GTX 2060, and will obviously be the replacement for the GTX 1070, and be slower than the GTX 1070, but faster than the GTX 1060, and they will launch the GTX 2050Ti at the £249 price point to compete, which will be a GTX 1060 +15%, thus completing the move up in brackets of the price for those card tiers. So the RX 590 will be stuck in the middle or on par, but with the games + freesync making it much more appealing.