Season 7 would be Harmon's sixth.

Nope.
Only Tennant episodes.

He's got a awesome sounding space opera show in the works, so hopefully he left DD because it's close to being greenlit.

Well, DeKnight said he left due to previous commitments, so that may mean good news incoming regarding his space opera.

I'd say it's a mix between the 90's armor and the black-ops-ish suit from "Secret War".

it does

Madame Gao's heroin bags have a Steel Serpent symbol on them, so she's likely tied to K'un L'un rather than the Hand.

Are we having fun yet?

The current plan is doing 4 13-episodes seasons, each spotlighting a Marvel street-level character (DD first, Jessica Jones next, then Luke Cage, then Iron Fist), with a bunch of plot threads in all of them converging in a team-up season (called Defenders, and IIRC planned to be 8 episodes long).

The Shield's final season had 9.

Nope, that was the garbage man. As @SunflowerFortunado:disqus said, it's what prompted the awesome "garbage boss" line.

"I lost a button."
"Maybe we all lost a button."

They have a new director of photography.
Not only are ther now outdoors stuff (the last time was in early season 3), but they got better at lighting the sets.

No it wasn't, and yes he was.

Please rise for the national anthem.
♪ For the red white and blue ♪
♪ For the funny things you do ♪
♪ America, America, this is you ♪

What are you gonna do? talk really fast over a beat machine?

I like the new pacing, I think the show's felt too frantic since roughly the middle of season 3. The scene with Todd or the Leonard bit in the cold would probably have been cut out on NBC.

It's hip hop. Of course it's bad.

Superfoop! Your trial isn't gonna be on national TV, I'll have to watch it on the Internet.
What if I get cyber-bullied?

Oh, really? Really, miss whatever-your-name-is, would a teacher who doesn't care bring in Rising Sun for today's class?