Not necessarily.
First deployment phase would actually take first turn. Yes. As it usually does anyway.
Attack declarations phase, Attack phase and Fortification phase as you call can happen in one turn as well, only not first one.
Only difference would be in order of phases:
Fortification phase (movement and reinforcement), Attack declarations phase, Attack phase
You can't do movement last because in one turn you can't predict where trupes will and up and in what numbers.
It could (if you insist) support as many chained attacks as one wants, but chain would brake upon troop depletion and one would have to predetermine with how many troupes attack would continue for each chain link. RiskII calls it Surge attack and allows only one per turn with 1 territory depth. That rule may as well be inherited, all doe not necessarily. Since everything is happening near simultaneously I'd drop it altogether and let the players resolve things one territory at the time to avoid any further confusion.
Therefore everything would still happen at once and in one turn with all players being done within 24h, with out the need for state checking in panic, like in Freestyle.
I'm not excluding possibility that lots of players might actually love rush property of Freestyle, I'm just not one of them.
Players' turns are actually just submitted settings of things to be done ones turn is ready to execute. Turn executes once last player submits its settings, or on 24h countdown from last execution, so all settings may as well happen simultaneously with out interferences or waiting for other players. Only thing to wait for is execution it self. One my even be able to reconsider and resubmit it's settings before it's to late, because it wouldn’t effect other players.
Because Fortification phase is first to execute players wouldn’t actually know exact location of enemy troupes (as in war one rarely does), but just the state they were in at the end of last turn.
Only thing missing is (step by step) animation one might observe instead of stumbling through log to figure out what has exactly happened once turn is executed. It would be nice to have such animations in all games. In more detailed animation one's luck/unluck with dice would also be visible (maybe even scientifically studied).
Yes, there is also problem with first deployment being based on each players turn, and rest of turns being execution based, but you are bunch of smart people, so I'm sure you'll figure something out.
For those unfamiliar with “SameTime” mode from Risk II:(I thought it was well known, my bad)
Execution resolves in this order (not necessarily in Conquer Club version):
1.
Border clashes – when two territories are both attacking each other (two invasion forces meet)
2.
Mass invasions – when one territory is being attacked from multiple territories by one or more players.
3.
Invasions – one territory attacks another territory.
4.
Spoils battle – if Mass invasion bay multiple players is success, surviving invaders fight each other for territory.
5.
Surge attacks – chained attacks
It is actually much simpler to download game and try it out in its 20 or so minutes of demo then it is to explain all that's going on in it.