I have to disagree since right now they're pretty much well developed. Orginally they only cared about finding the treasure and had no interest in protecting Earth or it's people. But now they're more willing to fight for it.
I disagree with this assessment of the show's plot. The Gokaigers clearly never only cared about the treasure, this is very obvious from a close viewing of even the very first episode. They make that claim, but whenever someone is being abused right in front of them, they step in to help.
Gokaiger's real character arc is that they begin the show too afraid to fight Zangyack whole-heartedly, but then Gai motivates them to become a true Sentai by giving their all to topple an evil empire. Several episodes reinforce this theme, particularly the Death of Warz Gil episodes and the Jetman tribute.
Thing is, if that's all the characterization the Gokaigers get, then they're poorly-developed characters. In a show with well-developed characters, say Shinkenger, I could write a full 200 word paragraph about the mannerisms, motivations, and inner conflicts of each of the main heroes.
If I attempted this with Gokaiger, some main characters wouldn't get past a second sentence. I could probably manage a full paragraph about Ahim and Gai, but the rest of the characters are far more archetype and exposition than an attempt at making a fictional person.
As much as I agree with you, if the Gokaiger don't end up getting a Returns Special.............do remember that they are also one of the major characters in the upcoming Rider VS. Sentai crossover movie involving Kamen Rider Decade this May.
I don't think that'll have anything to do with it. Goseiger Returns came out around the same time as 199 Heroes in Japan, and this just resulted in a line of voice-over narration in the special letting you know that Goseiger Returns happens before the events of the Legendary War as shown in 199 Heroes.
If Toei wants to do a Gokaiger Returns alongside Superhero Taisen, I'm sure they'd just take a similar approach. It's not like Gokaiger Returns would have the same director or staff, anyway. Superhero Taisen is mostly in the hands of the Rider crossover movie crew.
The ratings for Goseiger also weren't that much lower than Shinkenger.
Goseiger, much like Shinkenger, also hit a demographic that likes to buy crap for their favorite shows, too. The ratings wiki is putting up demographic spreads for various shows and this reveals a lot about how those shows ended up being marketed. Shinkener, for instance, did really well with M1 and F1-- people in their early 20s, basically.
Goseiger inexplicably did really well with teenagers. This is pretty baffling, because a basic rule of modern tokusatsu ratings is that only the biggest hits draw any teen audience at all. So Goseiger could've benefited from bleedover from W, which also drew a much larger-than-usual teen rating.
Otherwise, I can only guess teens were tuning in for one of the lead actors/actresses. For comparison, Shinkenger I think never managed even a 1% teen rating, I think Gokaiger has some eps with 0% teen ratings. The last Sentai Japanese teens tuned in for regularly before Goseiger was Magiranger.
While the difference between Goseiger and Gokaiger is more or less the same as Shinkenger and Goseiger, I imagine Gokaiger's low average won't do much to make Toei want to make a Returns special.
If you look at the demographic spreads for Gokaiger, the only audiences it does really well with outside of the usual Kids block is M2 and F2-- that is, men and women in their 30s, people who have probably watched Sentai off and on for most of their lives. This is an audience that could probably support a Returns special, especially one with guest stars.
Really, the only sort of Sentai I could see not being able to support a Returns special would be a show like Go-onger, that didn't really do well in the ratings with any non-Kids demographic. In that case, the smart thing to do is just to move the kids on to next year's show, their attention spans are naturally short.
Indeed, Gokaiger's dvd+blu rays combined are selling about 3,000 copies per volume on its first week, which is not that much below OOO for instance, and way above Goseigers' numbers, that were so horrible that never got listed outside Last Epic.
You seem to have some odd ideas about DVD sales figures. Around 2-3K sales per volume are the baseline sales you can reasonably expect for anything new Toei releases. Goseiger's volumes that I've seen figures for have had sales in this range, so did Goseiger Returns.
Sales for a really popular show, say Kamen Rider W, are going to tend to be around 4-8K per volume. For a really huge show like Kamen Rider Den-O, you can reach the dizzying heights of around 30K per volume. Basically, Gokaiger's sales aren't really anything special... but neither were Goseiger's, and it got a Returns.
Maybe Toei just won't bother with v-cinema for Sentai anymore.
V-Cinema makes sense for any show with a big secondary audience (that is, any big block of non-Kids tuning in). I think Toei would be leaving money on the table if they didn't exploit Gokaiger's M2 and F2 viewers with a Returns, probably marketed as a thing for collectors like Goseiger's was.
(I think to get Goseiger Returns at all, you had to buy this huge memorial box that came with a big deluxe photobook full of stuff like episode synopses, close-ups of suits, and prop details. I figure something like that for Gokaiger would go over pretty well.)
Shinkenger Returns topped oricon with 20,000+ copies on the first week alone, which honestly surprised me for a series that used to sell 3,500~4,000 per regular volume.
An average volume of a show like Shinkenger (or Goseiger or Gokaiger, really) is competing with rental copies. Most people in Japan don't buy DVDs or BDs at all due to the high costs of media in that country. Instead, they just rent the shows. Most Japanese rental stores will keep volumes of modern shows (at least) in stock. Shinkenger Returns, I believe, didn't get copies released to rental stores ahead of its general release.