I don't see why Blaze needs to be replaced or indeed why Vue is the best alternative. Its a very nicely designed and implemented library and you get the benefits or vdom, better performance, components if you wish but I don't think it fundamentally changes the programming paradigm.
The value of React IMO is that it enables us to reason about and build declarative, data driven apps using mostly FP principles. That may sound like buzzwords but this is the primary reason it has seen such high adoption, not the fact that it added vdom or was from FB.
If I have to learn yet another DSL, I'd like to stay with Blaze and remain compatible. It'd be great if Vue were to become a first class citizen with official support from MDG, in the same way as React/Angular are supported as the rendering layer today. The other advantage of Vue us that its more prescriptive than React, e.g. including a router, and that is in the Meteor spirit of favoring convention over configuration.
Integrating with Apollo/GraphQL/any future data layer is also going to be a problem with any templating language, it simply cannot be done without extending the DSL. This is one of the real benefits of using plain JS everywhere as you don't have any restrictions.
From what I read, MDSG resources are limited and they have a lot of items on the backlog - Apollo, npm Meteor, webpack, all of which are priorities. Adopting Vue (either directly or underneath) doesn't seem like a priority above those, esp if work on Blaze2 is already far enough along.