Well, you find out later in the show that the Boukengers (and their mechs) are actually powered by preciouses. They also end the show with all their not actively used to power Boukengers and mechs perciouses destroyed. Perhaps with the mechs wrecked by Zangyack and the preciouses depowered by giving up their powers, they simply don't have the unique materials needed to repair the existing materials or build new ones. And without the Mechs or suits, it's too dangerous for them to collect what they need.

Gokaiger 22. It's like the show actually listened, no Gold Mode and a much more interesting mech fight!

It's funny, I found Joe kinda boring to begin with - ironically when he had the most amount of focus - but now the show has taken a step back and just let him be he's a lot more enjoyable. Like Marvelous he has a huge heart, that is always in the right place, but he just does things unconventionally which is a big part of the reason their bromance works so well. Plus it certainly helps that he doesn't overact quite like the actors for Gai and Luka do, even if in Gai's case it's intentional for the character.

Seeing the Dragon Ranger key and the Goseiger keys get used is my kind of fanwanking and the unmorphed fights in this show really are well done. I was so so about them at first, but honestly the suit actors in this show, weird height and build niggles aside, do some of the best jobs of portraying their characters ever even if stuff like the Dynamite Attack totally sucked.

It's been years since I felt like trying to watch a sentai series but something hit me and I just started. 15 episodes into Zyuranger which is farther than I've ever made it into a series, I think this time I might just finish it and go on to others. Started with Zyu because, y'know, MMPR in my youth.

I think I'm more interested in older series, but may give Gokaiger a watch next anyway. Read good things

Gokaiger is a pretty nice show. It gives you brief glimpses into older series and a taste of how they worked (Generally. Sometimes they just use the suits for the sake of using them, while others they go full on. Most series that get tribute episodes give you a good feel for their respective series, though).
If you don't mind a few minor spoilers concerning plot twists and deaths, then Gokaiger is great.

The worst part of Gokaiger, ironically, is the tribute aspect. Fans are quick to defend and make excuses, but the honest truth is sentai is a franchise of half baked ideas and a total disregard for any kind of internal logic or continuity. As such, Gokaiger is given a pretty rocky foundation to begin with, and rather than attempting to perhaps stabilise it or something....they just smash everything together, hoping the sounds of burning logic and the crash of conflicting ideas distracts you from just how stupid everything is.

Everything else though, is pretty damn awesome. The Gokaiger are cool as hell, the action is sweet...as hell and because the show basically has two types of episode 'tribute' or 'character focused' there has been no filler yet and I'm half way through the show, that has to be some kind of sentai world record. About the only time the show is ever boring is during the mech battles, but those are easily glossed over.

I'm not a fan of the tribute episodes, but it does give you a feel for how some series operated, like Carranger's.

I'm going to disagree there. The tributes were some of the best episodes such as the Car, Ginga, Oh, and Hurricanger ones. Oh yeah, and like the CarRanger one, the one with Jet Condor is one of the best episodes of the series.

The tribute episodes are a mixed bag. They're some of the best, but also some of the worst, episodes of the show.

It's hard to say they're universally good or bad because they're all pretty different and succeed or fail based on individual merits. Definitely inconsistent.

There have been some good ones, some fun ones, some utterly forgettable ones but it's the bad ones that stick furthest in your memory. GaoRanger and Boukenger I am looking at you.

The Boukenger one while rather useless for Gokaiger, is actually a nice little coda for Boukenger. While we never see Ryuon after certain event in Boukenger, he wias never really confirmed dead. So to finally have the confirmation that he did indeed die, and have him a true final fight gave me closure I had been wanting for years.