Concerning Kelly's comments about the "big change" moves being last year: I'm almost certain that he was talking about things which could affect the starting line-ups or the necessary major-playing-time guys. Theo Riddick was the most spectacular instance of that, but starting offensive line shifts were too, and later, Brian Smith to middle linebacker.
This year he said that the shifting will take place not at those levels, "but for depth reasons". What I think that he means here is prominently the O-Line. Kelly there has two things which are concerning him: 1). the structure of the BACK-UP O-line this year, and 2). the nature of the O-Line next year.
Concerning #1: Kelly has in his mind a three-guard rotation [Robinson, Watt, Nuss], which he sounds like he thinks will do all he needs there. He has Cave, who I bet he's praying makes it through the whole season unscathed, but has said that now he "trusts" Golic to be out there. He has his starting tackles, but what happens if one is hurt? Last year Dever went down and he had to juggle Martin over there and bring Romine in. This year he's putting Lombard behind Dever --- this is because I believe he sees Christian as the strongest upside of the guys who have been around [and maybe Zach wouldn't then have to move over] This leaves Nichols at LT back-up. Embedded in all that is a lot of "shifting" but for the exact reason that Kelly said: "depth".
Concerning #2: We're losing Robinson, Nuss, and, almost certainly [due to scholarship crush], Golic next year. Who's going to play right tackle? Who's going to play right guard? Lombard to right tackle may be telling us something about staff thinking. Because Zach Martin is such a stud, all our other potential spectacular left tackles either have to wait, or find something else to do. Hegarty is our best. Kelly is finding something else for him to do --- maybe be the best footed guard in the country --- something a spread-blocking-in-space team might like quite a bit.
We also saw other shifts more obvious like Farley and GAIII and Jackson and Collingsworth --- all "depth" issues. All this should make us feel very good: we are NOT desperately shifting "essentials", but shifting "supports" and future considerations. Pretty darn good position to be in. And, by the way: Kelly seems to be more "big picture holistic" in his team management than almost any "administrator" I've been a "student" of. I keep shaking my head in wonderment at the comprehensiveness of the man.