Edge will still be around, it will just be powered by Blink instead of EdgeHTML. So in theory Edge should have the same UI and feel the same when using it. But honestly the engine is not what prevents me from using Edge, it's the actual features itself compared to Chrome and Firefox.
I suppose it does mean they can redirect more resources to Edge's feature set to make it competitive, instead of spending a fair bit of time working on the browser engine to keep up with the competition. And considering how slow they were to update it (usually together with the major W10 updates), this could be good for both performance and security.
But that also means the only competing engine we'll have is Gecko, site designers will more likely target Blink/Webkit based browsers instead of sticking with universal standards due to the huge market share it will have. And Google being the developers behind Blink will mean they will have a lot of power on what sort of standards the web should have, just like when IE had a major market share and started introducing IE only features that killed off Netscape.