It should be noted that there's a nice vertical window in the room, similar to the one in Picard's ready room. Accommodating one of those anywhere between decks one and ten would be difficult.
So yeah, I think this Ready Room was indeed right off the bridge. But not necessarily where the room on the Enterprise was. The whole configuration of Deck 1 could be drastically different, since it was all supposed to be part of the module.
I don't remember exactly, but I think the window was supposed to give Maxwell a view of the Enterprise. Yet at that point, the Phoenix was facing away from the E and towards the (huge!) Cardassian triangular transport, so the E would be to roughly five o'clock from the Phoenix. This would suggest Maxwell's Ready Room was to starboard of his bridge, not port. It was also bigger and more rectangular, with a tactical display there - perhaps it served a different function from Picard's RR, and thus had more space dedicated to it.
And O'Brien did enter through a doorway, but that probably did not come from the bridge - otherwise, wouldn't the bridge crew have intercepted and apprehended O'Brien as he beamed in? Or had he already talked his way past that crew (which he probably didn't know personally)?
As a side note, I suspect the Phoenix was some sort of a "fleet sensor picket", a kingpin of the sector, with a mission of monitoring all Cardassian movements there using that roll-bar gadget. This would give Maxwell a superb position to deduce that the Cardies were up to no good, as well as to hide from other ships possessing lesser sensors. The interiors of the ship could have reflected that fact - perhaps all the SWACS data was piped up to Maxwell's RR in filtered form, to that big tactical display, where the Captain could make his big conclusions and decisions.
We did at one point see Picard talking to Maxwell over the viewscreen, but I believe at that point Maxwell was again in his Ready Room. But we did get to see a bridge of a Nebula Class starship, that was the Sutherland in 'Redemption'. It most unlike a Galaxy bridge, and not particularly attractive in my opinion.
-------------------- "To the Enterprise and the Stargazer. Old girlfriends we'll never meet again." - Scotty
But how does all this explain the potted plant..?
BTW, I really don't think the Sutherland's bridge set was its primary bridge. More likely an auxilliary control or battle bridge - after all, it *was* in spacedock undergoing repairs or construction. The only *real* bridge set we've seen on a Nebula was for the erstwhile USS Prometheus, which is merely a stock bridge with few frills. Still, it looked better than the Sutherland's...