Hmmm.....well, in that case I think I'm going to make two suggestions if you're just looking for anything. Heck, I'll even throw in a bonus one just because I can and because the bonus I'm thinking of is good.
First Pick: Kamen Rider Ryuki. Why? It's on the grey end of the spectrum without going too far into it. There's still a hero, there's still villains, but there's alot of people in between and there's alot of development and changes in people. It's not the most technologically advanced series, but what CGI it uses, it uses well. The ending may make you go 'wtf?!', but personally, once I looked at it in a broader sense, taking into account everything, I could live with it.
Second Pick: Jyuken Sentai Gekiranger. Why? Hey...I never said it was going to be ONLY Kamen Rider picks. Lighthearted, fun, but still has it's serious moments, Gekiranger encompasses all that stuff that makes you look back on Dragonball and DBZ fondly....only it actually has a story. It takes a little getting used to, and there's debate on if the mecha fights were too much or not, but the bottom line is the format and style fit, and to me that's what's important. I don't know about others, but the series ended with me sincerely wanting more in a good way, which is not something I can say for alot of other stuff in this Genre.
Bonus Pick Because I can: Keitai Sousakan 07. Why? It's just good, dammit. Do you need another reason? Good plot and character development, especially on the part of the main duo, and there's just some characters you learn to love. Combine that with a fair mix between wacky and serious stories and you have a good time. It's drama, it's action, but there's no need for men in spandex....unless you count that one episode...but...yeah.
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So there you go from me. Mostly my opinion, but I did try to back it up with what I could. I'm a fan of developing characters, although I suppose even that's subjective. Hopefully that gives you SOMETHING to go off of. Also, if you do watch KS 7, do so after Ryuki and see if you can spot a familiar face or two.