a rhythm guitarist is as important as other members of the band. i know some good rhythm guitar players na naging bandmates ko na rin. And they are VERY good at doing their thing. magagaling sila gumawa ng strum patterns. for me kase, ibang field ang rhythm at lead. hindi sya dahil mas magaling si ganito maggitara, sya na lead. no sir. good rhythm guitarists are good at creating grooves, mapapaindak ka talaga. they put in their accents dun sa part ng overall groove na wala msyadong nangyayari, (break ng basslines, lead lines etc.) if you heard a good rhythm guitarist na, you get what i mean..
.. i could talk about rhythm guitarists all day long, pero eto lang ang time na kaya kong ibigay.
oo, sabihin nating mejo mahina sila sa lead, pero i wont trade them to a good leadista kung meron na kaming leadista.
hope this helps. peace!