Vector Tile Layers Querying/Legends
Here is what my understanding was. They would pair it with a featureService for querying and symbology. The tile layer would be for rapid visual display; its twin featureService would respond to queries. In other words it would function like a featureLayer but ... way, way faster. For now I use map image/dynamic layers because I've found feature service layers to be too slow. Vector tiles held promise, I thought. Because seeing is believing, I went to Dev Conf this year and saw them tile all the roads in New Zealand in 30 seconds into 20 megs. So... I was sold. I was envisioning just running vector tiling on all our SDE layers that are in viewers every Fri night and so it would update over the weekend to a replicated wkid 3857 fGDB or something, to power viewers.
Now, the thing is we all want popups for our layers, and perhaps supporting querying and having symbology in legends and working like "regular" vector layers vis a vis feature services or dynamic services. I hope Esri can make this happen. Now.... In parallel, they've created the webGL layers. I tested those over the summer. Seemed like that was the compromise- lots of speed, while working just like feature layers. Well.. they usually didn't work, Chrome says there are too many "web GL workers" and it crashes or halts the page. In other words, after a few minutes I concluded the webGL layers are not ready for prime time. Whichever way they go, webGL layer or Vector Tile, I am looking forward to. Mostly for speed. Users have a "need for speed". 
These both look promising.
