For starters, they removed the cliff.
The tavern isn't in the same place, neither is the blacksmith, I don't get this either... hell, they don't even have the pier they used to light the bodies floating out to sea.
Checked some things, but it's easy to see where the confusion comes from. While it's not on the Dragon Age wiki, here's from an interview with Mike Laidlaw:
Mike Laidlaw: Yeah, Fereldan is in fairly rough shape actually. I mean, the Fereldans are tough; but they’ve had to rebuild in a lot of ways - most of the South fell to the Blight, Redcliffe Village had to rebuild after being sacked and Darkspawn were still active. You do run into characters who have ties back to Loghain, the events of Ostagar, what happened to the original Redcliffe; all these things will come up and you get hints of how Fereldan’s been doing. Now, it’s had time to rebuild...
(Source: http://mmgn.com/ps4/...ew-bioware-talk ).
And...
The events of the Ferelden civil war left Redcliffe in tatters. Its reconstruction has been a slow process, but the city has made a remarkable recovery after its ordeal at the hands of young Lord Connor Guerrin.
After the battle of Denerim, Arl Eamon gave the arling over to his younger brother in order to devote his full attention to advising the throne. He left the new Arl Teagan with the monumental task of rebuilding the town and perhaps the even greater challenge of dealing with the influx of mages into the area following the breaking of the Circles.
From The Changing Face of Thedas by Sister Petrine, Chantry scholar
I stand corrected regarding the possible destruction of the castle, it's nowhere actually stated this happened or there was a major rebuilding of it. It came up in some threads discussing the visual discontinuity; since Laidlaw mentioned the destruction and rebuilding of the village, it was speculated the same thing happened with the castle itself. That would explain the fact that the castle doesn't look like anything like the DA:O original.
As for the layout of the castle, you can find the actual maps for DA:O Redcliffe Castle here http://guides.gamepr...ide.asp?ID=8623 and for DA:I Redcliffe here: http://guides.gamepr...de.asp?ID=27981.
They are quite different, but both are merely rooms-and-tunnels dungeons, and not actually complete buildings with more or less corresponding interiors and exteriors, as with Skyhold and some other keeps in DA:I or Kaer Morhen and Kaer Trolde in TW3. The problem with dungeons is that they very often can feel the same because there are only so many ways you can combine tunnels and rooms.
But in general: There is very little continuity between DA:O and DA:I Redcliffe. The name, the location next to a lake and the possible presence of Connor are the main links, sort of. Personally I'm quite flabbergasted they even put the location in the game, it's not as if people can't see 'continuity issues' coming from a mile away when you revisit an old but major location. If they called it 'Castle Schreck' nobody would have complained. IF, on the other hand, they had taken meticulous care of ensuring a degree of visual continuity they would have been praised.
As it is, there's apologists, critics and the uninterested. It shouldn't have needed apologists.
Sigh. As with so much in life, it probably looked better on paper / as a model etc.