72x speed means the same speed we have now. 1x speed means the same time scale as adventure mode. Dwarves would be going at the same speed in 1x mode as they are right now.
This might clear a few things up: http://dwarffortresswiki.org/index.php/Time
There was a discussion a couple pages back about the problems the current time scale causes. It makes interaction between Fortress Mode and Adventure Mode a lot more problematic, for one. Also, it means it takes a dwarf several weeks to walk over to the other side of the map.
I understand that. But if the dwarves' actions were made to take as long as the do in Adventure mode, then everything needs to be changed to the adventure mode speed- including, for instance, water flows and other processor-intensive things. If all of these things are made to occurr 72x more frequently than they do now, where is the extra processing power going to come from?
Well, but I think the idea that people were talking about a couple pages back was that the game time would just be 72x slower, so you would still get ticks at the same rate, which would mean things don't need to occur 72 times more frequently in
real time, so you wouldn't need a much faster processor. It would require recalculating a bunch of things, such as the liquid flow speed that you mentioned -- although it might be that that's another thing that currently makes more sense at the adventure mode speed than at the dwarf fortress mode speed -- but those are just things Toady would program the numbers in for ahead of time.
Actually running the game such that a tick occurs 72 times as often is another question, and that is actually quite interesting. You would avoid many of the problems with the game getting boring, or various events such as trade caravans and invasions happening way too infrequently in real time to be interesting (whether you agree with such assessments or not). You wouldn't need to abstract things either, such as the pathing. You would still have the issue that things would be hard to follow, but that might not be too bad, it's hard to say ahead of time. Of course, the problem there is, as you mentioned, limitations in the available hardware (especially if you did still want to show every tick on the screen). But by the time something like this would be implemented, we'd probably be many years further down the line, so I think it's a very real possibility to take into account.