Hmm I say in 2014/5? Hopefully by then PS4 will be released, and then SCVI can have a graphic makeover (SCV looks great, but it didn't push major barriers since SCIV). Namco wasn't very keen about giving Daishi enough time to polish SCV, so will they even consider SCVI in the first place >_<?!?
(Going off a tangent from here on)
I think SCV is a great game, but I find I'm playing it less often lately, mainly because I really miss offline modes like Survival mode which SCVI doesn't have. Playing online is fun, but I get annoyed when I frequently get booted from player rooms >_<! The ragequits ruin it too. The loss of many characters like Cassandra really hit me hard too T_T!!!
However, I really enjoyed SC since SCII. I had lots of fun playing VS mode with my siblings and trying to break records in Survival mode. It would be such a shame for SC to end in the future, since there is so much going for it T_T!! I truly wish the SC series will continue on in the future!!