Some good feedback there - thanks! No promises, but I've passed this on to my Home Appliance colleagues - who will feed it back to the relevant folks at our end on your behalf.
On the specific points you raised:
1. Voice Control: No launch date for voice assistant in the EU as of yet - but there are ongoing discussions towards this. Related to this, (and your other thread) no further word on Bixby for the product yet.
2. Mute: If you click the "i" button at the bottom right you'll be able to mute the volume either by sliding the volume to 0 or pressing the speaker icon with the line through it directly to mute it immediately. System volume and touch sounds will still function - but these can be switched off/muted within the settings menu.
3. Spotify: Premium is indeed a requirement for Spotify Connect. However, you should be able to use Tune In player and/or the web browser to stream music from other sources.
4. TV streaming: Due to the complexities of screen mirroring and controllability it's limited to models sold after 2015 "H" series and also above the "6400" number. This is to ensure this feature is consistent, reliable, and secure, and is built into the software of the TV.
5. DLNA: A great idea! (Apparently, some of the guys at our end have raised it before - but they're more than happy to get customer voices added to theirs.)
6. Supported Flash Player: Good suggestion, but unlikely to be implemented due to the greater push towards HTML5 for website content.
7. Skype/WhatsApp support: Looks like the initial thinking was that people would be more using their mobiles for this, but your suggestion has been fed back.