Be glad.
If he had stayed, Addazio would be our non-official head coach (or actual head coach). We would be getting excellent two star recruits out of New England. We would still be playing statistics (dive play every other play). We would still have a whole bunch of transfers every season. We would still be beating FSU in players arrested.
Now, if he gets an OC who isn't a yes-man, they have a chance. Otherwise, it will be a "run over the B1G patsies, lose occasionally, get blasted by the SEC or other powerful team in a BCS bowl" program.
True, tOSU will have to get rid of that offensive coordinator and get a top guy in there if Meyer will have success there. He's not a playcaller.