Everything the show did well:
-Really unique team dynamic where the whole team are jerks, which makes the build up to them becoming a proper team feel great and natural.
-All team members stand out and are constantly entertaining, the commander is also really fun.
-Extremely entertaining and likeable villains.
-Really entertaining and memorable monsters of the week.
-Cool and creative fights both in mecha and outside of mecha.
-Great final arc.
-Cool rivalries with the villains.
-Unique atmosphere mixing romance J-dramas with military kodomo shows and a dash of insanity.
-Some of the most memorable episodes in the entire franchise.

Everything the show did bad:
-The team tends to get their upgrades in really convoluted asspulls (but I found them entertaining so I didn't mind it as much). This makes the writing feel cheap at times.
-The Neo Jetman two-parter sucks for the most part despite the cool concept.
-Blue ranger Ako, yellow ranger Raita and Commander Aya get considerably less screen time than the other 3 members. But they still manage to be extremely likeable so it's not that big of a problem.
-The main antagonists being extremely powerful but not fully using their powers to compete with themselves is not a premise for everybody and can make the writing feel cheap. Personally the villains' charisma made them super likeable throughout and never minded this but felt like pointing it out.
-The ending is controversial and not for everybody, personally I didn't mind it.
-At times it feels like the white ranger Kaori doesn't get reprimanded enough for her actions, but this is mostly a nitpick.

Reasons for the show's strengths:
After having 9 shows in a row done mostly by the same staff Super Sentai was struggling to stay afloat and considerations for the franchise to be canceled were rising. Due to this chief producer Takeyuki Suzuki chose a young staff that didn't have much experience because he wanted this season to be fresh and also a team that understood that this could be the very last Sentai after promising the sponsors that the sales would go up this season. He got Keita Amemiya to direct who at the time had only directed a non-toku movie and few episodes of previous Sentai and Toshiki Inoue to write who was the son of veteran writer Masaru Igami but had only served as an episode writer for Sentai up to this point.
Despite the decision of choosing this staff was deemed controversial at the time, they made the most unique Sentai that had been made up to that point, one that's considered to be one of the best still today and it's also considered to be one of the most influential Tokusatsu of all time.
The production team tried a bunch of experimental tactics and didn't care much for the sponsors' suggestions since they thought this could be the last one and wanted to do unique stuff just in case.
The producer chose to have a female commander and introduced the concept of "Boy" mechas that served as helpers to the team.
The director came up with ideas for cool props to use in the earlier episodes and for more creative ways of doing the mecha battles.
The main writer came up with the idea for the show to adopt tropes from trendy dramas, which the producer supported him due to having previously worked on Toushou Daimos which also had romance tropes. He also wanted episodes where te team didn't transform and while Toei and the sponsors didn't allow them to realize this idea, the director supported Inoue and made it so that not every ranger had to transform every episode with the exclusion of Yellow Owl and for the cool Black Condor broken helmet scene. So this back and forth arguably gave even better results.
Other experiments by the staff was the villains not having a proper leader, the team calling themselves by their real names after transformation and the team not getting along for the first half of the show which lead to really interesting dynamics.

Reasons for the show's problems:
The main writer Toshiki Inoue didn't really for promoting toys so Jetman's upgrades would often either come out of nowhere or be obtained in a really conveluted manner. He also was really interested in the romance subplot of the show so Raita and Ako got slightly shafted. His writing is pretty insane so the story at times feels not that concise.

Overall:
Amazing show that redefined tokusatsu when it released. The writing is not the most concise but the show manages to be extremely entertaining from beginning to end (with the exception of the Neo-Jetman 2-parter). This was the show that got me into the Super Sentai franchise and highly recommend it to tokusatsu fans or people that are searching for a weirder romance drama.