4 studio sends is not enough when trying to provide monitor mixes for more than 4 musicians playing live ( a small Band for example).
I suggested this some time ago in the N5 forum and several other users responded that they too would like to see more than 4 Studio Sends.
Inserts, Sends, Direct Routing all have 8 slots per channel, so why not provide 8 Studio Sends as well?
+1 !!!
+4 would actually be ideal ! 
Page 254 of the N6 user manual refers to cue sends ‘…meeting the needs of the individual performers’. However, if we just take a small rhythm section and a single guide vocal (Guitar, bass, drums, keys and a singer) that is already five people probably requiring separate cue mixes. Throw in some brass and a percussionist and the limitations of having only 4 studio sends in Nuendo become apparent.
I appreciate that it would not be practical to have an unlimited number of sends, but being restricted to just four sends in Nuendo is very often not actually ‘…meeting the needs of the individual performers’ - it feels as though Steinberg see the whole Studio Send facility as a token gesture, a bit of a toy that nobody is really going to use.
From my own point of view, 6 sends would be better, but 8 would be great.
I always thought that one of the main reasons that only four Sends were provided in Nuendo was due to space issues - the way each send was displayed in the mixer meant that four of them could be made to fit nicely in the same space as eight inserts; but the way things are now crammed in in N6 that idea probably doesn’t hold water any more and it should be quite possible to squeeze another four in.