You're certainly right about the uncertain future with the Q400s and like I said, I don't mind doing 15-16 days rotations every month for a few years but I highly doubt that anyone will be pleased with his social life if this continues for the next 20-30 years. Flying 747s to exotic destinations is nice but will certainly not help to forget the time you won't spend with your family & friends, especially not after 5-10 years.
I would try to join CV immediately if I only knew that that there might be a chance that things get better someday because at least in LG I know that the roster cannot become much worse because we're already pretty close to the limits.
Of course everyone has different priorities in his life and I'm looking for a company in which I can stay till the pension (if only possible) and that's why I don't think that CV is the best choice if things remain as they are. I could be wrong but I don't believe that many will stand the test of time at CV if things don't improve.