The major external differences between the refitted Enterprise and the TNG era ship are the third nacelle and the Big Gun. The former sits, as said on the specs page, on a large pylon between the existing pair. It is visually identical to the originals, but all three now have a prominent box like structure on their upper surface. Each of these has an additional phaser array mounted on them. The single phaser array on each of the original two nacelle pylons has been replaced with a fin like structure flanked by two arrays, giving the ship sixteen visible arrays in all. Including the one which is presumably still hidden within the ships separation plane would bring this to seventeen arrays total, but for the purposes of the specs page I have not included this last one. This is because it looks to me like the big gun on the bottom of the saucer is joined onto the ships connecting neck, which may well prevent separation. If so then this last array would be unusable, and would presumably have been removed. In any case, the specs entry refers to visible arrays only so it's covered either way.

Like other vessels of the era the ship was able to travel at Warp 13 and some have taken this to indicate a third recalibration of the warp scale. I prefer to think of this as indicating that the Federation finally conquered the transwarp drive, and for my own speculative transwarp scale you can check out the "Sci-Tech" button above.

The Big Gun is often called the "Phaser Lance" by fans, but I don't know if that is official or not. While the beam it fired certainly looked like a phaser beam I haven't done more than suggest the connection on the specs page, simply calling it a beam cannon. The guns performance was pretty amazing; we don't see the results of its first shot but the second punched a hole straight through the forward hull of what would soon become known as a Negh'Var class ship.

As well as the nacelle and weapon, the refitted Enterprise had some other modifications. There were two appendages placed on the saucer near the bridge; these look a bit like forward pointing cannon of some sort, but could equally be sensors or communications equipment or pretty much anything else you want to make them. The area behind the bridge has also been built up with a box like structure.

The neck connecting the main and secondary hulls also had a boxy structure attached. This covered the old impulse engine, replacing it with another on the back of the box in the same location. The last change I can make out is a pair of fin like structures on the outside of the nacelle pylons, about where the phaser arrays are on the current version.

The All Good Things model was later modified to become a more standard Galaxy by having its various doodads removed. However, while the third nacelle was removed the structures on the top of the other two were not. This model was seen as the USS Venture in the episode "The Way of the Warrior". I think this was probably an accident - though it's just a feeling, I have no proof one way or the other. Either way, it does make a lot of sense - if Q was projecting Federation technology into the future to create a simulation, or was actually putting Picard into one possible real future, then the Venture becomes a nice stepping stone between the two. The Venture also presumably represents one of the "combat biased" Galaxy class ships discussed by Rick Sternbach. These vessels are said to have no science labs, holodecks, or other non-essential items. As such they are easier to build, a useful measure with the Dominion war looming. Enhanced engines and an extra pair of phaser arrays would also fit a more combat oriented ship well.

These ships may be the "uprated" Galaxy class ships mentioned in the DS9 Tech Manual. These are claimed to be capable of Warp 9.9 compared to the standard Galaxy's Warp 9.6. But caution is always advised when using non-canon sources such as Tech Manuals, and most especially this particular book. This entry alone contains at least three other mistakes - the ships height is way wrong, and the phaser and torpedo armament is also in error.

The refitted Galaxy class also breaks two of Gene Rodenberries claimed Starship design rules; namely, the pylon supporting the third nacelle breaks the "nothing between, behind or in front of nacelles" rule, while the nacelle itself breaks the "nacelles in even numbers only" rule. Although other ships have broken the latter rule before, none have been so prominently displayed on screen. One could claim that this doesn't count since this future was an invention of Q, but one would expect Q to be mindful of such things - he would presumably want to make a future which was creditable, lest he make Picard realize it wasn't real.

Naturally, the destruction of the Enterprise-D at Viridian in "Generations" makes at least this part of the "All Good Things..." future redundant, so we will never see this particular ship again (unless you count reruns, har har). But we could eventually see ships of this type again - if we ever see a film or series set in the future, a Galaxy refitted in this manner as a background ship would make a nice tip of the hat to TNG, much as TNG and DS9 drew so heavily on Excelsior and Miranda class ships.