Thanks! This was very informative, and explains a lot.
I agree: try as they might, warp speeds could not be used consistently in TNG either. If the story demanded that they return to Earth now, get from the Neutral Zone to any other place now, then that's just what they did. The fundamental problem is that the galaxy is much bigger than anything that makes Star Trek feasible, probably even by the 23rd century.
Not only that, but the spoken dialogue complicates matters further. Consider this:
Most consistently, starships throughout most of TOS, TNG, DS9, ENT and even VOY, typically are ordered to lumber along at Warp 2, give or take. Sometimes they may go Warp 3 or 4, but faster than that seems to be almost a special occasion. There are many occasions where Kirk and Picard simply order Warp 1. If those speeds are relatively slow in the galactic scheme of things, such an order would be frivolous at best.
We could retcon and assume (without any canon evidence) that starships typically surge warp velocities after such low-warp orders. But there are other indications which lead me to believe that would not be necessary...
In DS9's "Emissary", when Sisko's Runabout first passes through the Bajoran wormhole, Sisko uses the Runabout's computer to determine their location based on the exploration of a probe from the 22nd century. Based on what we know from ENT, it seems highly unlikely that such a probe, even from a few decades after "All Good Things..." would be able to manage a speed better than Warp 3. I think Warp 2 would be pushing it.
And in TOS "Friday's Child", Sulu muses that "the best a frieghter could manage is Warp 2", to which Scott admonishes "I'm well aware of a freighter's maximum speed, Mr. Sulu." And that's in the later half of the 23rd century.
So if non-military probes and frieghters aren't expected to do better that Warp 3, for sake of argument, even in the 23rd century, then how do probes manage to check out the far side of the Galaxy?
Let's assume that probes of the 22nd century were slower, maybe only Warp 1.5. Now, let's assume that one of the new Federation's initiatives was to launch enormous waves of probes all over the Galaxy to learn and explore. Say, in the 40 years from 2161 to 2201, the young Federation launched at least 10,000 probes, and of those probes, most reported back from at least the first leg of their voyages. But the further they get away from home, the more likely they would be to be damaged or destroyed by natural phenomena such as quantum filaments, ion storms, dark matter/energy, or hostile aliens. So maybe as many as 99 percent of the probes eventually parish in deep space. But many of them do send back telemetry and at least 100 of them survived to fully explore their assigned routes.
If we follow Cochrane's Formula from MAPS, at least some of these probes may have been able to navigate along routes where Cochrane's Variable would be favorable to warp travel, even at speeds under Warp 2. So it would be entirely possible for a few of the probes to make it to the far edge of the Galaxy well before the DS9.
