With the third season, ENT was given an upgrade to improve the poor viewer numbers. Still, it didn't help. After four seasons it was still over.
The worst opening theme in the history of Star Trek now rocks with a beat - unfortunately that doesn't make the song any better. If the showrunners had had the courage to admit that this song doesn't fit Star Trek and replaced it, that would have been at least a sign of courage.
T'Pol not only got a new hairstyle that makes her look more feminine, but also new outfits. Gone are the days when she wore dark jump suits. Now she wears red and light blue jump suits - with a neckline that shows more of her skin. Speaking of skin: T'Pol is once again used as a cheap vehicle to attract teenagers (like Seven of Nine). This time there are even boobs, albeit covered by her hands. Why the hell couldn't the showrunners think of a better way for Jolene Blalock than to constantly reduce her to her appearance? Seven of Nine at least had an interesting storyline of her own and was absolutely essential to most of VOY episode's plots.
The Enterprise finally has photon torpedoes and the crew must now deal with a threat never heard of in other Star Trek series. The Xindi want to destroy Earth because their world will be destroyed by humans in the future. But why they first test a weapon on Earth before delivering the ultimate blow and thus giving the humans time to counterattack remains their secret. Just like how five completely different intelligent and sentient species managed to evolve and coexist on just one planet.
I also wonder how the Enterprise manages to fly through the expanse when both Vulcans and Klingons have encountered sheer horror there and lost ships. Ships that were more technologically advanced than what humans are now sending in. And by the way: According to ENT tradition, Archer is kidnapped again and finds himself a second time in a mining facility as an involuntary forced laborer. It's getting boring.