There was a 21-page critique of the series finale floating around the net someplace, but a cursory search didn't turn up anything. Off the top of my head, there was (SPOILERS) Janeway ignoring the temporal time directive, her admiral self deciding to show up then to save the crew rather than, you know, the very first time that Voyager was chasing the Maquee around in the nebula in the Alpha quadrant, the fact that the Admiral gives tech to the Captain rather than the Admiral just doing it with her own ship, the fact that nobody on the ship steps foot on Earth or that the celebration at the end of the series is barely two minutes long... Yeah, there was badass weaponry and all, but there were too many plot holes to make it a practical ending. But that's just me.
Arr, here be SPOILERS Janeway was never one to fully follow the rules throughout the series. She bent the rules of the Prime Directive countless times - and that was one thing I liked about her. I mean, face it, the Federation's "non-interference" policy, while it's good most of the time, doesn't apply to certain situations. Because of this, I don't think it's out of character for her ignore the Temporal Prime Directive.. I always figured that "future Admiral Janeway" probably knew she had to go back to that specific point in the timeline, because that was the crucial moment to defeat the Borg and get Voyager back. Admiral Janeway giving tech to Captain Janeway? Not sure about that one. Never thought about it much before. It's been a while since I've seen it so I don't remember all the small details. As for them not celebrating/setting foot on Earth; I liked it. It was simple and clean; looking out the viewscreen and finally seeing Earth. I don't think they needed some long, drawn out celebration at the end with streamers and music. Star Wars already did that...and it was cheesy. You want a bad ending? Go watch Enterprise! (LOL) You'll think Voyager's ending is amazing after seeing that crappy episode. Oh, I forgot. We Enterprise fans aren't supposed to talk about that episode. It doesn't exist.