Episode #60http://rapidshare.de/files/2140020/Ishikawa_Rika_-_Chanchaka_Charmy_2005-06-02_n60.mp3.htmlPurpus, you're right on. Rika's strengths are that she has a lot of emotion behind her voice and more often then not she CAN hit the right now..
I'd tend to agree with
Masa and
Fenrir13: Rika's voice
has improved. If you compare 2001 Country Musume/The Peace to last year's Otome Gumi concert where she pulled off "I WISH" ... she is louder and her voice doesn't drown out. And it's not just studio magic, the self-made tunes she sings on Chanchaka Charmy prove it. They should have the "Don't Say The Last word" game on HM again so we can hear Rika sing solo lines.
I'm not really interested in that generic JPop voice (either faux soul like Utada Hikaru or faux whiny like Ai Otsuka) ... from Miki to Takahashi to Risa, it all sounds the same to me. When Rika steps up to the mic, it's different. You notice. You go "goddyyyammmn there she goes again! opening up her piehole!!" that makes her unique. combine the charisma, that makes a superstar. that's why she's a natural to front v-u-den. she owns the audience and it more than makes up for her vocals. it's why Tsunku is so in love with her voice and will keep giving Rika opportunities despite popular opinion.
Rika herself has admitted that her voice becomes monotone whenever she emotes like when it's high when she speaks or when she tries to sing low key. Her voice really fits the trance tunes she much enjoys. Ajaisai was a perfect fit for her!!
Besides, with idol music whether Erika is singing all the lines and Yui is bouncing her boobies - the media will be talking about Rika and fans will still be cheering for Rika. Erika has an amazing voice and Yui can hold her own but they have to stop being intimidated by Rika. Loosen up and Viyuden will be unstoppable (
Call her Rika-chan DAMMIT) Rika has more than 4 year edge on them, but that's no excuse.
Hell yeah, I can listen to her voice all day. She has the most comforting speaking voice as well, not too high, not squeaky like some others. The single most distinguishable voice in all of Hello! Project, I guess people are still put off by her owning The Peace in 2001 as she burst into the spotlight. Rika's no Celine Dion and I like it that way.

Yay for RIKA becoming host!!!
Haven't watched the episode yet, but anything with RIKA is ought to be good!
Go conquer the world RIKA! 
It was SO GOOD. I just watched part of the main segment, and she was a natural. This was the complete Rika Ishikawa. No goof ups, she kept the show running smoothly and kept everyone involved.