If we hypothesise further, the Astrometrics/Stellar Cartography room in GENS was considerably different to the one we saw in the television series, so maybe all of those areas were given an upgrade for some specific mission that we never got to hear about?
Why would the Stellar Cartography Department only have one room available? The ship is gigantic - there would probably be a laboratory complex with two dozen rooms for the department, including a big show-and-tell facility that the scientists themselves would have little use for. It would come in handy when impressing visitors, though.
In Encounter at Farpoint there are actually 4 corridors that run into engineering.
To be exact, the forward two weren't just "corridors". They were doorways, seen closed - with the doors set at differing depths in the corridor at different times. "The Naked Now" had fairly deeply inset doors:
The pilot presumably had almost flush doors, as per this publicity photo, even though this area was not filmed.
You cannot even use the excuse that the corridor was always there since All Good Things shows us engineering from before the pilot and the computer walls are in place just as they had been the rest of the series.
Considering they kept the telltale carpet, it should be simple enough to believe that the computer walls were indeed temporary, movable things even in the Star Trek universe. That is, they could be installed or removed at a moment's notice.
That sort of thing might actually make some sense. Remember the first-season runabouts in DS9? Access to the supposed amidship and rear facilities was blocked by a glowing green wall where a doorway would later exist. A clever fan once suggested this green thing was a big computer cube on rails, something that could be pushed back for access to the middle space and then further to the container midsection and the stern lounge, but would typically lie flush with the cockpit wall because this piece of modular survey equipment was of great and regular use to Sisko's team - greater than the aft spaces, which really only were needed on long trips which Sisko seldom made. Or the sliding cube might be the interface for a midsection payload that wasn't crew-accessible.
The computer walls on the E-D could well slide out on the flat floor and be rolled away along the spacious corridors at the "bow" part of the set. At least if they were no deeper than the depth at which the doors are inset in "The Naked Now". "Modular" works fine there, too. And is all the more plausible if only one of the modules is removed...