I don't think 8mm Titanicus would matter- the fan sculpts of the various titans are much, much bigger than anything GW ever released anyway (including the Forgeworld line of Epic Titans). GW would simply be shooting themselves in the foot regarding infantry and vehicles- money here will come mostly from us old-timers. Still, size isn't a big deal in Epic for the most part, so I can see 8mm being used alongside 6mm.
It'll be similar for a Warmaster re-release. If they don't go 10mm it'll just cost them money, and those who buy it will probably run it alongside 6mm stuff anyway.
If they make Warmaster into an AoS game I have no interest.
Agreed. I don't really care what they do to the rules, as we have good rules we can use with any suitable models now. If they make the models 'AoS' styled though, or based on AoS factions, then I wouldn't touch it.