CCP has announced a fairly radical change to the ice mining system of EVE. You can read that at their devblog on the subject, here.
... the current static (and massive) ice belts spread throughout space will be removed from the game, and replaced by a series of Ore Anomalies that will spawn and respawn only in systems that previously contained the aforementioned static ice belts. These belts will respawn in exactly the same system four hours after they are completed, to ensure that players from all time zones will be able to partake in ice harvesting and enjoy the spoils. The amount of ice found in these sites will be tuned to ensure that most, but not all, of the ice needs of the New Eden cluster can be provided by high security belts. At our current numbers, the maximum supply of ice from highsec (assuming that each belt is mined out completely five times a day) would provide approximately 80% of the game's ice needs, ensuring that at least some of the ice mining must be undertaken in lower security space. For context, this means that highsec will still be a large exporter of ice products, being able to generate eight times the volume of isotopes used by highsec control towers.Why is ice priced as it is? More generally, what determines the value of highsec ores? On the one side, demand for building various stuff. This won't change with Odyssey (or it will change very little). On the other, supply. Miners mine for ISK, and all mining is basically interchangeable. There are very mild differences in skills between mining ice and other stuff. But basically, mining is mining. Miners don't care what they mine; they care about their costs -- mainly, getting ganked; they care about how easy it is to mine (more on this in a second); and they care about how much ISK they earn. Thus, in highsec (where everyone is safe), miners should be expected to make the same amount for everything they can mine for equally easy mining. Because if any one price goes high, every miner has the incentive to switch over and mine that ore instead. (And same if a price goes low.) And we can see this is true: check out the ore prices at Cerlestes. As of this writing, the worst highsec ore is getting about 10% less than the best. And the price of ice is, as we expect, pretty uniform across ice types.
Why is ice not competitive with highsec ores? Ease of mining. Currently, ice asteroids never deplete. You can mine ice completely AFK: fly to the ice, target it, turn on ice miners, and walk away. Depending on how large your ore hold is and what boosts you may have, you now have 20 minutes to an hour completely free. Walk the dog. Cook dinner. Watch a movie.
We can see how valuable being AFK is: ice currently pays about a third of what ore pays. There are a lot of miners exploiting the ice system. Some are bots or hardcore multiboxers. I've seen obvious multibox (or robot) setups of 10-20 miners. Many others are just AFK or semi-AFK solo players. I sometimes icemine with my market alt, when there's nothing particular for him to do.
So what about Odyssey?
The price of ice will skyrocket, because there's just not going to be enough in highsec for solo bears to get. Even after people adapt (and they will), spreading out to cover all ice fields equally, there is a hard upper limit on ice. Because of this, we can make one easy prediction: the value of ice (in terms of isk/hour) must rise to equal the value of highsec ores. This is not saying too much, since ore prices are likely to decline somewhat (more ore being put into null, and also, what are all those ice miners going to be doing for 4 hours in between ice pulses?). Still, we can expect ice prices at least to double.
Will anyone mine ice in lowsec? I doubt it. Much too dangerous. Today one can mine decent ore in lowsec grav sigs (and with moderate safely), but very few players do that. Higher value ores pay little better than lower valued ores; again see the Cerlestes page. The best ore (Arkanor) is just 60% better than the best highsec ore. Even forgetting about the difficultly of finding Ark in lowsec, the pay does not make up for the time lost any time you see probes, and the occasional gank. Nor can it make up for the inability to leave the keyboard.
If ice goes high enough, some might be mined in lowsec. But it would have to be very high indeed, enough so that a well-organized group of miners including dedicated escorts could still make much better money than they do in highsec. But if you are organized and groupish, you might as well mine in null. It's safer.
So, I expect that 20% of the current highsec production of ice will be mined in null. In null, at least, we can expect ice will have to rise in price to compete with whatever else one can do in null for money. Given that one can earn ~50m/hour running anoms, that's an upper bound. Both are about the same danger; a mining fleet is easier to kill than a PVE ship but also cheaper. Ice mining in null would still be possible semi-AFK, and as such is much easier to multibox. I expect most null ice mining characters to be a member of a multibox (or bot) group. So, I expect somewhat lower earning, perhaps 25m/hour.