I'm actually kind of glad Novak is gone, his character has been worthless since Season 4; I was ok with him getting hired by Michael for the MS Paper Company but when that went away his character needed to as well. There's no way Wallace would have agreed for Ryan to come back to DM, even as a temp.
And I'm not shedding a tear for Kelly Kapoor being gone either, another character who's been pretty worthless a while now.
Dropping 3 worthless characters since last year (Ryan, Kelly, and California, a character they ruined) would actually given me a bit of hope if Tate wasn't coming back. After Dwight leaves for what I assume will be a failed spinoff, it's really going to suck. Since Paul Lieberstein will be over Dwight's spinoff he's not going to be on The Office much this season either. Again less could be more but I'm guessing since it seems they dont' know what they're doing anymore, they'll probably bring in more silly replacement characters.