I agree, the signings aren't headline-grabbers but they are definitely solid signings.
Savage in place of Zola seems a pretty straight replacement, O'Callaghan for McLaren, the buzz seems to be that the new lad is attack minded and gets in the goals. Sonko for Davies and Edds for Jennings (perhaps, or Stockdale).
Anyone who expects Ronnie to dramatically change the formula this season is deluded, but I'm quietly confident that the singings made will be as good as the players who have already left and perhaps even a little better.