Len/Ren's voice wasn't so bad for me, but maybe it was cause I grew up with it. Funny thing for me was that Len was chinese and had the english accent, while Lyserg from London didn't xD
I would love to get a reboot of Shaman King! Especially with that anime only ending (I didn't read the manga ending back then), but it was just so unsatisfying for me seeing as they put off the Shaman tournament saying it was postponed.
Shaman King itself was pretty popular for it's time, but was cancelled suddenly.
According to
wiki, Shaman King got around 26ish million (as of 2011) which isn't too bad whilst HxH and FMA both got around 65ish million (of course idk how accurate that list is, can't find a list with more than a top 10 or 20).
Even more so with Shaman King Flowers still currently being released. I haven't read the manga yet, but I would love to see the sequel of Shaman King get an anime with Asakura Hana. I know that the sequel's apparently ended as well last year.