After skimming through all the posts, here's some of my thought's on what's being discussed.
* Yes, Dekaranger is episodic with very little of an overarching plot, but it's episodic done well. While it was new to Sentai at the time, I'm assuming it's nothing new to most users here who have either watched Power Rangers in its early years or watch American TV in general. What I like about Dekaranger is it manages to deliver an interesting storyline each episode related to its cases or characters. Dekaranger has some of the most well remembered episodes in Sentai, like episode 17 or even 37. What amazes me with these two episodes is how Dekaranger manages to execute comedy very well in one episode (17), and drama in the other (37).
* In regards to Umeko, yes she acts childish and ditzy, but she pulls it off in a fun way. Like FL said her actress plays the character really well and isn't annoying like Akiko from W. She's not all that dumb, and had some of her best moments when she showed competence when needed, like using drunken boxing to beat a drunk MOTW, or willingly going undercover in the dream world to save others. That's far more than I can say for Houka (I wouldn't put Natsuki in Houka's position either).
* A lot of Jasmine's appeal is her actress's looks, and no one including myself will deny she's an attractive woman. However, I think among all the characters who get the fanboy praise (including Nanami, Miu, and Luka, who I also like to some degree), she's executed the best. Her backstory with how she learned to deal with her ESPER powers really brought out the best of her characters. Her actress did a great job of portraying the different emotions her character had to. She has some quirky dialogue as well, but that's what I think made her fun. I can't imagine liking the character as much if she wasn't making those sarcastic remarks, like imitating the Abaranger theme song.
In fact, I think all the Dekaranger actors in general did good with the characters they played, though Hoji's actor did slip a bit on a couple scenes. I can't really imagine any other Sentai actors portraying these characters the same way that the Dekaranger actors portrayed them.
About the villains, I think it's hard to judge them since there's only one main villain and the MOTW are all independent agents. I think Abrella served his purpose. He was an arms dealer behind the scenes, and I think did his job well. He's nowhere near the best villain, but was good for what he was.