To begin with, the scientific/technical inconsistencies were completely over the top, even by Star Trek standards. If you want a good exhaustive list of all the specific things this movie got wrong, this post and the hundreds of comments following is the place to go. I don't have the energy to deal with all this in detail, but I will simply say this: in the original series, most of the fanciful violations of known physical laws were there because, quite simply, none of the stories could have taken place without them. We needed "warp drive" to get to other solar systems, "subspace communication" to keep in touch with the rest of the known Galaxy, "matter-transporters" to go places not served by airstrips or spaceports, "phasers" and "photon torpedoes" to do just the right amount of damage without having to wait for missiles or artillery rounds to get to their targets, "communicators" because we didn't know to call them "cell-phones" yet, "tricorders" and "sensors" to find out what was going on without wasting too much air-time with CSI-style detective work, and "Class M" planets and humanoid aliens all speaking English because there wasn't enough money for better effects. And besides, the series' original creator, Gene Roddenberry, wasn't in it to write science-fiction in the first place; he was in it to write about socio-political issues, and only had to cobble up the space-future stuff to get the socio-political commentary past a media establishment of post-McCarthyist wimps. So it made perfect sense for this series to sacrifice technical realism for the higher goal of telling stories that drove home messages.
It should also be mentioned that the original series came out during the 1960s, when it looked to most of us like science and technology really could do just about anything; when it really did seem that sooner or later, we would indeed be travelling faster than light and solving all manner of problems by taking all manner of unrelated gizmos and connecting them with duct tape or subspace channels in new and ever-more-wonderous ways.
Today, we roll our eyes and laugh when a guy with a hair-holder for eyes says something like "If we use a spoo circuit to reroute enough fleem plasma into the warp-core, we just might keep the containment field going long enough to get out of the Neutral Zone." But let's face it, that's only a more fanciful expression of how we use, and invent, technology to solve real problems on the fly; and how real people did indeed solve life-and-death problems both in modern war and in real space travel (note the use of duct-tape and three-ring binder covers in Apollo 13).
In the latest movie, however, all the gizmos and inconsistencies simply got out of control, right along with the unending noise, insane camera-work, and excessive bash-'em-over-the-head nonstop-shoot-'em-up action. In the original series they served the plot, which served the specific message; in this movie, they completely overwhelm the plot, which doesn't seem to serve any coherent message.
And once, I got the impression that the makers of this movie were going out of their way to mock the technical-realism criticism. I can't help thinking that the water-processor scene in engineering was a direct homage to the banging-metal-plates-of-death scene in Galaxy Quest. (What other purpose could that scene have served?)
It was certainly a lot of fun seeing all the old characters in their earlier years as they were just getting to know each other and finding their proper places aboard the Enterprise. That's pretty much the whole purpose of this movie; and quite frankly, as good as it was, it could have been a lot better with a bit less action-for-action's-sake packed into it like drunk football players in coach seats on an already-overbooked flight. The people who made this movie were trying way too hard to substitute action for character-development, and it showed. And it was kind of sad, since they had good actors playing very interesting and well-loved characters at what must surely have been a very interesting time in their lives. The actors, and characters, would have shone more brightly had they had more believable problems to solve, and more believable situations in which to show their stuff.
I consider myself a stickler for technical realism; but as long as the overall story and characters are believable, I'm willing to tolerate a few lapses for the cause. When too many such lapses combine to make the overall story implausible, that's when the story becomes crap and I start to tune out. This movie couldn't stay internally consistent even in its first third, which to me shows extraordinarily poor writing, lack of imagination, and unwillingness to stick to some semblance of reality. And it was reality, dressed up in futuristic costumes, fake ears and prosthetic foreheads, that made the original low-budget morality-play known as Star Trek, worth watching: they cut corners on the science, but never on the reality of human life. In this movie, however, that reality, that striving for relevance, has simply been overwhelmed and shouted down by people who really didn't seem to have anything to say.
As for specific characters: my second biggest complaint on this issue is that they had James T. Kirk, not just as an arrogant punk, but as a self-destructive arrogant punk; which is not a good quality for a starship commander to have. And how does such a punk get himself promoted to captain of a ship to which he wasn't even officially assigned? If he got away with that, it's no wonder he got away with violating the Prime Directive so many times since.
But my biggest complaint was about the treatment of Uhura. The Enterprise communications officer was: a) a woman of wit, education, culture, dignity, and honor; and b) one of the first, if not the first, major African-American characters in a major American TV show. Her importance as such, and the fact that Martin Luther King Jr. went out of his way to recognize it, is a major bragging-point for hard-core and soft-core Trekkies alike. While Zoe Saldana did an excellent job of playing the younger Uhura, the scriptwriters did an absolutely wretched job of writing for her. For starters, a romance between Uhura and Spock, apparently well underway by day one of the Enterprise mission, was simply not...logical -- and the chemistry just didn't show on screen.
As much as I enjoyed this Star Trek movie, I would have enjoyed it more if the producers had shown a little more understanding of what made the original series, and subsequent spinoffs, so great in their own right; and had had less desperate desire to use the Star Trek name to add luster to yet another sci-fi shoot-em-up. Loud noises and over-the-top effects are not necessarily "revitalizing."
And no, they didn't "reboot" the franchise, they pretty much destroyed it: after a rock-'em-sock-'em battle of this magnitude, with such high stakes, at the beginning of the Enterprise mission, what can anyone do for an encore? If you're going to top all previous movies and TV spinoffs, don't do it in a prequel.