The biggest hole we need to patch is the O-line obviously. I am somewhat optimistic that it will not be much worse than this year's line, given it's dismal play. A couple key jucos will mean the diffence between an average unit and a bad one.
As some have mentioned, I think we are also very thin at RB. Scales can't block and will get hurt. Kock will be sorely missed in short yardage. Hopefully someone can step up.
We may see some competition at QB since Brett will not have the "experience running the offense" advantage over Arnaud. Recievers should be solid for another year. We saw that these players can't do much without an O-line though. Our offense will depend on how well we can rebuild the line.
Defensively, I am not as optimistic about our D-line as some people. We lose the two best players on it in "Big Play" Curvey and the school's career sack leader in Moorehead. Tuba lacks some speed and endurance and Frere got pushed all over the place when I watched him last year (which is why Tuba played so much more later in the year).
Our linebacking core should hopefully be the bright spot we had hoped they would be this year. Bowen and McKenzie clearly have a lot of potential, and should improve under the guidance of the new coaching staff. Carper, Banks, and Garrin will all also be in the mix. There is a lot to work with in this group.
Our secondary will also improve next year. The loss of Jackson is big, but we have a lot of guys with experience coming back. Singleton should improve and we just picked up that juco recruit who should compete for a starting spot. James Smith should be healthy again next year and be able to compete for the starting spot at free safety. Who knows who will be at strong safety. We could see Harris stay there or Banks move back there given the talent at LB. If we play the Tampa 2 style everyone has been talking about that should also help take some pressure off of our corners, but could expose our safeties more. This group's performance will depend on whether the D-line can get any pressure.
Special teams wise we will see Shaggy and Brantner again, and both are quality players.