In general there are two rules when thinking about changing Catalyst. The first is technical merit of the idea. If there is a bug, then its obvious it needs to be fixed. Less obvious is the types of refactoring that went into giving Catalyst modern features like websocket support, interoperability with event loops and to expose more and more of Catalysts PSGI underpinnings.
When an idea has strong technical merit, it recommends itself. The only thing to consider is the needs of backward compatibility, and to offer people upgrading at least some sort of path forward when features change (such as to have plugins or configuration options to replace or replicate something that is no longer available).
Then there is a second and more difficult type of change consideration, which is the general will of the community. Like technical merit, this needs to balance against our commitment to not leave existing users high and dry with changes that break code and offer no path forward that does not involve significant code rewrites. Unlike technical merit, the will of the community can be hard to figure. In general we dont get a lot of bug reports or conversation around Catalyst future evolution. I wish I could find a way to get more involvement, but I also understand this is not very unusual issue for open source projects. I personally dont believe that silence is consent either. I think choices need to have broad acceptability or the choosers lose respect and authority. Typical that results in people just drifting away.
Without direct involvement the only other way to measure the will of the community is to look at what other choices people are making and what other projects have received the acceptance of a broad number of people. Since Plack is clearly accepted and important it leads me to feel the choice to make Catalyst expose more of its Plack nature and to better play with the larger Plack ecosystem are correct ones. One can also pay attention to the kinds of problems that get reported on IRC, at conferences and the problems that I see having looked at how Catalyst has been used in the wild. For example its clear that Chaining actions could use a tweak in some way since it seems to trip up people a lot. The same goes with $c->forward and $c->go, which tend to lead to confusing code (and combined with the stash is a particularly toxic brew).
Going further, if we allow ourselves to look hard at projects outside of Perl we can get lots of great ideas about what has worked for other projects in other languages. When we see certain features and approaches have excited programmers using frameworks like Ruby on Rails, Django, Scala Play, etc. then it should provide us with with help in thinking about how those features might influence the evolution of Catalyst as well.