1. The tram approach on the Green line is still silly
Let's start with the "bad" (which isn't that bad since I like the extension overall). Because it's an extension, not a new redesign of the whole line, it is of course running the same kind of train as the rest of the Green line, and the Green line runs trams.
Some are nice and new
But they're still trams. High-floor trams, even, so it takes steps to get up into them, which is not best practice. They are relatively low capacity for their size, and especially on the grade-separated extension line it's ridiculous to be using these instead of the actual metro cars on the other three lines.
2. The stations are nice but a bit separated from their neighborhoods
I like the stations themselves. Good wayfinding, good bike parking, nice-looking.
But as you can also see here, the station footprints themselves are quite large, and don't integrate cleanly into the neighborhood around. It's a missed opportunity for development of density immediately upon the stations, and it's also related to the tram issue: because the tracks are on the surface, you can't build above them as easily and so they take up real estate rather than appearing above or below it in an elevated or subsurface line.
They've done well with these, but the inherent limitations are visible precisely because of that.
3. They genuinely are an improvement
For all that: I really like this extension. Not only does it bring additional capacity to underserved parts of the metro area, the way it's implemented connects nicely and easily to the city center and existing lines. Interleaving the D/E sublines of the Green line (don't get me started on the choice they made in the past to call this one line) with the extension and clearly split them from the B/C lines (no A, sorry, RIP) makes the map much better than I'd worried it would be when this was first mooted. And the service itself is pleasant, with decent speeds for the tram style in North America and comfortable relatively new trams.
The Green Line Extension could have been done better, but the perfect is always the enemy of the good, and this is, in the end, good.
