If state wide pre-emption on OC isn't passed this year to protect open carry state wide the anti's will pounce on the first sign of weakness and that failure would the be the first sign I think.
I don't think we are at such a critical juncture. Two years ago 2A movement got nothin'. Last year we got a few things. According to the NRA maps we will have more 2A legislators over the next 2 years and a governor who, while he hasn't always fought FOR 2A rights, he historically doesn't stand in the way of them either. Heck,while AG, his office was one of the most aggressive in the nation pursuing reciprocity. While a lot of that sits on the diligence of the assistant assigned, he appointed the man and he didn't get in his way.
Anti-gunners in MO seem to consist primarily of a handful of rather wealthy people from areas around Branson, Columbia and St. Louis. People in this state (and country) are in no mood to be told by urban liberals and wealthy elites what is good for them. So I don't think the opposition primarily lies there although there will be some potent wealthy forces against us in Branson, Columbia and St. Louis.
I live in SE MO where the newspaper somewhat recently wrote that a huge percentage of households have firearms (IIRC it was over 80%), where firearm ownership is just normal. Off the top of my head I could name a dozen people I know professionally who hunt, shoot, conceal carry regularly AND are definitely opposed to OC and furthermore, support the City of Cape Girardeau's ordinance prohibiting it. I heard most of these anti-OC sentiments when putting out some feelers about trying to get the ordinance repealed. These are the people who make my state rep and senators squishy on the idea while they are strong supporters of CC.
So, while I would love to see OC pre-emption in the state and I will certainly work towards those ends, I don't think that we are at some critical juncture where it is next year or never. Then again, I've been busy with other things for several months and you may be aware of something I am not.