It certainly would've been jarring for Riker to suddenly be a more junior officer, perhaps even taking a back seat to Worf, as it's not all that certain Picard would've made him second officer, given the fact he was eight years behind in terms of starship operations. It would've made more sense to promote Worf to the position of second officer, actually.
Certainly, renewing the romance with Troi in itself would've presented some good storylines, and would have precluded the short-lived Worf-Troi dalliance. They probably would've married and had a child by the end of the series.
And for Data, it would've been a tremendous opportunity for his character as well -- another step in becoming human, learning to manage people rather than systems.
There would have been a different dynamic between Data and Riker. As you may recall, Riker voiced some distrust of Data in the first ep. I can imagine Lt. Riker would've been even more vocal, having to take orders from an artificial man.
For Jonathan Frakes, it would've been an acting challenge for him, something he probably would've welcomed, as Riker's character had stagnated somewhat after The Best of Both Worlds. Frankly, Riker at that point should've spun off into his own show as a full Captain. Always wondered how DSN would've developed with Riker as station commander. They certainly could've written in that Riker's mother was a Prophet who posed as human, then went back to the Celestial Temple when she died.
But is it true that DSN only wanted two TNG characters to move to the show? I know they wanted Ro originally, but it turned out it was first O'Brien, then Worf.
Red Ranger