I agree with RF14 that this hire is going to be huge for the Rams. And the reason for that is Foles. Foles struggled last season due to degrading fundamentals and Weinke is going to be all over that. If he can get him back where he was in 2013... We will have ourselves a fine QB.
And then of course the rookie QB and importance of the position along with Foles' impending FA must be considered. So, yeah, there is a chance that the OP is correct in that this hire might be the biggest single addition for this team this year.
Lastly, I really look forward to seeing him and Cigs work together. If they perform the way I believe they are going to, teams are going to be interviewing Weinke for OC next year. Sure would be nice to see teams looking at the Rams' offensive coaching staff for hires, wouldn't it?