From this interview (which is a good 'un) - it's clear Podcat attempted to design the game such that it wouldn't need to pause - while that actually means notifications are more important than less (if there's less time to scan around the map, surfacing info becomes critical), I suspect what it meant was that a robust notification system was never part of the initial design.
Also part of the interview though - despite the devs' best attempts, it turns out we actually really like being able to play-and-pause:
Not a surprise to any of us - I've been arguing a "one-size fits all" system is inherently anti-accessibility from the beginning (because it is, by definition). But now that it's been acknowledged by the former game designer that the (in my view, given the complexity of the game, somewhat optimistic) attempt to move away from play-and-pause wasn't successful, it makes for a decent argument to implement a robust, optional (as per the above, a one-size fits all system means a small proportion of players love it, and the rest have to suffer it) system of information surfacing to players with optional pausing.
Given the effort spent on supporting multiplayer, when it's a tiny fraction of the playerbase (see quote below - note, I'm not suggesting doing less for MP - I'm a big fan of a game supporting a diverse audience), it wouldn't seem that it would be an inappropriate use of resources, relative to how audience size (noting that, of course, those decisions are up to the devs, and I'll respect what they decide to do one way or the other). Bear in mind that the proportion of players that used pausing notifications was something like 50% larger than the entire MP playerbase, and ridiculously larger than the large online group competitive playerbase.
