Star Trek Generations. One year after TNG goes off the air, the crew of the Enterprise D takes to the big screen. Earth is not endangered at all, not even by Dr. Soran...not many fraks were given by the audience at all.
-Strengths: Excellent acting by the cast. The Enterprise D's crash sequence was somewhat good. Commander Data's reaction to seeing Veridian III coming large in the window: "Oohhhhhhh....sh**!"
-Weaknesses: Overblown episode. Small screen writers and directors trying to make a big screen event, and falling far short. Visual effects didn't look all that different from the series that was on the air just the year before. (Although it was nice to see a return to the photon torpedo effects I loved so much in ST:TMP
). There was just no quantifiable jump from the small screen to the big screen on a visual level.
Star Trek First Contact. Earth (in two eras of time) is again implicitly endangered by TNG's most popular baddies, the Borg. A bit easier to engage audiences with such a threat.
-Strengths: A bit of an improvement in the visual area, but still not quite up to big screen snuff. Good story, and some good character moments, especially between Picard and Lily. Loved the new phaser rifles.
-Weaknesses: Still looks like an overblown episode. Visuals filled up smaller screens (4:3 aspect ratio) a lot better than on the big screen. Enterprise E looks like a toy, rather than an impressive capital ship. Biggest weakness... movie blew its wad in the first ten minutes with a space battle that fell way short in terms of bang for the buck, and lasted about as long as a typical episode fight.
Star Trek Insurrection. Earth is in no way endangered. Instead, we are exposed to a conflict between two alien races that no one in the audience is familiar with, and not exactly compelled to feel for, unless you are so invested in Amnesty International that total strangers are worthy of your pity.
-Strengths: Good humor, but Worf starts his descent toward being more comedy relief than anything else. Nice tie ins with DS9's Dominion War storyline, good for fans and admirers...not so good for newcomers and casual movie goers.
-Weaknesses: Yet another overblown two hour episode in terms of story. Visuals were decent, but again, nothing we hadn't really seen on Voyager...so again, as with the prior two films, no big leap to the big screen.
Star Trek Nemesis. Earth is endangered, but only by orders of Praetor Shinzon, near the end of the film. The Reman Warbird Scimitar has a weapon of mass destruction aboard, but never gets underway to Earth.
-Strengths: Finally looks like a big screen film, largely because they had a big screen director and a big screen writer. Action fills up the 2.35 to 1 aspect ratio nicely. The space battle lasts practically the entire second half of the film. The Enterprise ramming the Scimitar was worth the price of admission. Tom Hardy as Shinzon...in acting terms, a breath of fresh air from previous heavies.
-Weaknesses: The attempt for this movie to be TNG's "Wrath of Khan". The fanboyish, and rather incorrect technical story devices of screenwriter, John Logan. This film essentially fractured an already unstable and factionalized fanbase. Essentially, almost the final nail in the coffin for a franchise that is about to be taken off life support.
Star Trek 2009. Earth is endangered, and a fan favorite planet is wiped from the galactic map.
-Strengths: Big budget investment results in big budget looks which makes for a blockbuster film. Excellent visual effects, except for the omni-present lens flares. Good story loaded with fun and good drama. Appeals to more than just the niche Trek audience, it draws in a general audience that would never have given Trek a second thought otherwise. Altering the timeline to allow fresh stories and fresh takes on beloved characters to be told. Edgier than Trek films from the past. Blows away all previous Trek box office records.
-Weaknesses: Those lens flares! Some of the liberties taken which again factionalizes some of Trek fandom, who seem to think that the original series universe has been swept under the rug, when it is constantly iterated that no such thing has happened.
Star Trek Into Darkness. Earth is once more endangered, this time not only by potential war with the Klingon Empire, but by the hidden machinations of Khan Noonien Singh.
-Pros: Again, blockbuster budget and visual effects. A much edgier Khan, who kicks more *** in two minutes than the original Khan did in Space Seed and TWOK combined. Highest grossing Trek film of all time.
-Khans: Perhaps an unnecessary revisit to familiar territory...at least this movie does not try to disguise its "Wrath of Khan"-iness unlike Nemesis.
Those are my opinions only.