sharke
Do you think a 7 string guitar would be harder to mix and more prone to muddiness?
Interesting question. I would think that it would at least sound cleaner than a 6 strings tuned down - but that's an uneducated guess, based solely on the fact the fact that you have access to a bigger string to handle those lower notes, instead of just reducing the tension on a regular E string. I could be totally wrong, though.
The guys in Meshuggah play 8 strings and they sound darn tight as far as I'm concerned. The bass player must hate them, though. ;)
That's also admitting that you also have the right cab. Those guys playing 7 strings seem to like oversize cabs - from what I understand it helps pushing the ugly resonance lower so that it contributes to the massive low end instead of just muddying the low mids.