If you go in without preconceptions, the plot's fairly decent - if a little Swiss-cheesed by editing that probably was more the distributing studio's fault than the original script's.
I saw no similarity to Outlanders at all, unless you're referring to the end-parts of the manga (which I never got a chance to read) instead of the OAV. And how many people here would be that familiar with a manga, anyway?
Little Star Trek II, either, except the most vague of parallels because of a similar plot driver in the form of a planet-creating device. You'll note that "Bob" when created was barren of life, from whatwe see when they are on the surface. The Titan vessel just had a repository of DNA for recreation of the life forms, not the quasi-mystical ability to create it from nothingness. At least the Titan was significantly big enough to have served as a means of such, compared to the Genesis Device.
Most of the other references I saw were mostly tongue-in-cheek variety, not rip-offs.
One of the big criticisms is, "Why did the aliens attack?" and related to it, "Why did the aliens fear the humans?" Unfortunately, that's one of the things cut from the movie - probably by the releasing studio, out of fear it would be "Too much science" for the viewers...
Let's see... from the background info, including the Dark Horse Comics prequel trilogy (not read the novels), humans were one of the late-comers to space. Earth had no major colonies outside the solar system (i.e. bigger than 5-digit population, by my best guess) because life turned out to be so common, most planets capable of supporting life, already did so in spades, and if they weren't populated by an indigenous intelligent species, then someone else beat the humans there by thousands of years. And all those races were content with living in artificial environments, instead of trying to convert whole planetary environments to better suit them.
However, most of space society had been stagnant (in terms of creativity) for as long. Humans were actively being human, with all the creative thought and "Who says those are the rules?" mentality that goes with it. Humans were the only race to even consider developing Terraforming technology worth researching, because of its cost and resources required. Original Terraforming research projects got canned 300 years before, when the technology first because feasible to work on an existing planet, because the only planet easily worked on in human hands (Mars) was already too populated to evacuate in order to begin the process - and so were most planets in other systems in their "life zones", one would imagine. Most research beyond that point was in the avenue of creating a new planet.
That's what scared the bad-guy aliens so badly - the idea that this upstart race could destroy centuries, if not millennia, of status quo by creating their own worlds, and having a monopoly on that technology. With it, humanity would conquer known space within centuries, just through colonization and breeding. Then, there's the unwritten, unmentioned (compared to Star Trek II's plot) of such a conversion being used as a weapon - humanity, truthfully, never even considered it, from the comics so far (2 or 3 out). On the other hand, once the kid's father got the ship hid, he might have added those breakers as a means of repowering the ship if it got attacked - by that time, he KNEW who and what the enemy were, and the ship's power reserves were low enough to make risking that kind of recharge/defensive system worth it.
Away from the plot - the standard animation was up to typical Bluth standard, which meant I found it okay (except for those annoyingly huge mouths - too used to anime, I guess). The computer animation was well done for the most part, but for every part where the CG fit in seamlessly with the art, there were some real honkers (I wish they'd been a bit more creative with the ice rings' components). Also, if the regular animation had been just a little bit brighter, some of the CG would have seemed less intrusive - Bluth's style of dark-tinted animation made some things stand out that wouldn't have in, say, a Disney movie, or most anime.
The music was excellent, and a far cry from what I was expecting of a Bluth film going in. Brian's planning on buying the soundtrack when he can actually find it. I ending up missing the "race" scene because of the call of nature, but those who attended the showing with me said the action and the music that accompanied it made the mixed graphics not stand out as much as the CG would later in the ice scenes.
On a scale of 1-4 stars, my view:
Art: ** (if it had been a little brighter, instead of DB-drab, it would have been 3)
Plot: ** 1/2 (would have been 4, had the plot points raised in the prequel comics actually been in it)
Music: *** 1/2
On another note: I found it interesting that the one national reviewer that is a personally-stated anime fan - Roger Ebert - gave it a glowing review. I believe his review gave it 3 1/2 stars.