Given that 491 is (apparently) designed to ease pressure on Melbourne and Sydney and disperse immigrants, I'm interested to see what the response will be for the 190s.
A lot of the 491 will go to 85/90 pointers also as they will apply for both visa as it always happens as a back up (they may move to 189 once that one comes also but once visa is issued, it is counted and hence DoHA is not going to reissue visa again, so even less than what it is).
I'm not so sure. 491 is likely to be a pretty involved process and I imagine a similar cost to 189, 190 & 489. You'd have to be pretty desperate (and wealthy) to actually go through the process of applying for 491, and then do it all again for 189. So I guess someone could hold on to a 491 invite for a few weeks in the hope of scoring a 189, but I wouldn't think that's too significant a number. Holding a 190 as insurance? Maybe. A 491? I don't know....
Regardless, the shape of Australian immigration is shifting again. Good luck to all involved.