I have a Wave and am amazed that you found it unstable. My son cant tip that thing over no matter how hard he tries. It is the last boat still out on our lake (Cayuga Lake in upstate NY) when the wind picks up. However, I wouldnt get it for a family outing. It is really just a trampoline with nowhere to lean back and nowhere to store anything except by tying it onto the tramp - goes fast as hell though. It does have a jib option but dont get it - the mast is stepped too far forward for there to be any kind of a reasonable slot when the (tiny) jib is up. We dont use it.
No, it wont point all that well but makes up for it by being fast. I havent sailed the Hunter 170 but my son has. He says it is a wet boat but that is no different from the Hobie where you might as well consider it as going swimming. Tacking is always a bit hard in a cat especially when there isnt a jib to backwind but with practice you can do it.
For me, a hobie is a great toy to get out on when the wind picks up. A wave is much less prone to pitchpoling or tipping over than a 16 is, but it really isnt made for a family daysail.