It might be worthwhile here to consider how game development often happens at the big studios.
You do a lot of pre-production design, and get started on your tool-building and asset pipelines. The publisher cuts you a check that looks huge. You hire a bunch of people.
Around the time you're really starting to make progress on implementing your foundational systems, a VP from the publisher shows up. After being shown the early character builds and environment/object assets, he (or she) declares that it all sounds good but it's missing a completely irrelevant and complex mechanic that he saw once in a completely dissimilar game. Also, E3 (or some other trade show) is coming up, and do you have a playable demo containing a full vertical slice of the game yet?
On being told no, the VP for Clueless Intrusion tells to to do it anyway or you won't get the next milestone payment you have to have to keep paying all the people you hired. Oh, and it can't delay the planned launch of the game for next Christmas.
The project plan has not yet been written that can cope with interrupts like this.
But you dutifully update your project plan, anyway, and redirect everybody to the new short-term goal. You know, and everybody else knows, that it will mean cutting some features from the game that actually ships if you're really going to hit that marketing- (not feature-) driven timeline, but you set that aside for now.
Everybody works insane hours to deliver a more-or-less working demo for the show that highlights some of the core features of the full game you want to make (including some mechanics you'd wanted to reveal later as part of your phased PR plan, but oh, well). It's sufficiently well-received that you get your next progress payment. You go back to working on the actual game.
One day, about the time your core systems are done and you're deep into content generation, you're summoned to see the publisher's CEO. You show him the game whose features you've been explaining consistently to his VPs for several months now. He nods, then casually expresses his opinion that your first-person parkour game would work better as a third-person game. (Note: this is
exactly what happened to DICE when they showed what became Mirror's Edge to then-EA chief John Riccitiello.)
You narrowly escape having to entirely redesign your game, but you still have to crunch again to hit Marketing's timetable, and only at the cost of shrinking some of the levels and cutting several mechanics. The game launches to a media blitz, but is drowned out by other games vying for a share of the holiday game sales pie.
The game is immediately savaged by critics and gamers as an incomplete, buggy mess. If it was a sequel, you get emails to your private, personal account threatening the lives of your family because you "destroyed a once-great franchise." After a month, your entire team are fired (via an email sent by the same VP who wanted the E3 demo).
Now -- contrast that to Josh's situation. He is fully aware of the tension between finishing LT and making sure it has the features and polish it needs to substantially achieve its publicly defined design vision. As the sole developer, not beholden to the whims of any publisher's wallet, Josh is free to decide which individual features will best satisfy the goals of time and quality. Sometimes that's going to mean changing or adding things that weren't part of the big-picture plan.
That's not "lack of focus," it's flexibility of a kind that managers of publisher-funded games can only wish they had. I suggest that we should be thrilled that Josh is open to implementing features no one could have thought of any sooner that -- in his opinion -- add substantial value to the game. That IMO is more important than hitting a magic date in a planning document that's built entirely on estimates and guesses from the past.
I manage projects for a living. I know the value of hitting a schedule. I also know that Josh is working under different constraints than mine -- he's creating an entertainment product, which means greatness > immediacy. Make it great, and no one will care when it was released.
My vote, if I had a vote, is for letting Josh seek greatness.