Prefacing a lengthy post, so TL;DR - we do lose some of our better guys, but overall where our biggest loses appear to be (OL/DL) I think we'll be able to recover without major issues.
Based on the OP's list it does appear that we lose some of our top end guys, but as others mentioned we might be OK given the experience some younger guys are getting this year. I don't think anyone will ever confuse us for Alabama or Ohio St. plugging guys in year in year out, but I think overall we should be pretty comfortable going into next year.
DL - losing Ott and Meier will be big, but return Johnson/Bazata/Faith in the middle is huge. Ott being hurt this season is sort of a blessing for 2016 in that Hesse is getting some valuable experience. We should still be really good vs. the run. Don't forget that Nelson and terlouw are getting lots of meaningful reps this year also. Nelson's development could be the key to how good that line can be next year. he is guite a specimen.
LB - Fisher is having a great season. Not too concerned with Jewell and Niemann returning, plus Bower hopefully will continue to improve or at least we should be able to fill the 3rd LB spot with someone serviceable.
Some of us have already said that there should be quite a battle for that 3rd sport, but no matter who wins it (i think it's bower), i believe we are in great shape there!
DB - Really hoping King stays. If he does, our secondary will be great. Not that losing Lomax will be easy to overcome, but I think we'll have enough talent to find someone. Also big is Josh Jackson has looked pretty good (imo) for his first time at CB and should only get better.
OL - Losing Blythe will suck big time. Losing Walsh will suck only slightly less. We do return our tackles, Croston (who I haven't been high on so far, but maybe he's a guard next year?), Daniels (Center or Guard?), and Welsh. Add in some young guys and I'm not too terribly concerned about OL next year. Don't know why your not 'high' on croston so far, but the coaches are (as am I) and they went into they season with myer 1A and croston 1B at left tackle (according to KF). I have said numerous times that croston will be the RG next year unless he beats out Myers, than Myers will be the RG since iowa puts their best 5 lineman on the field.
WR/TE - Losing Tevaun will hurt, but hopefully Jerminic can step up. Otherwise we still have Vandeberg and McCarron, but really hoping another young guy can step up as a "playmaker" (Scheel???). HKC and Duzey leaving won't be good, but Kittle has gotten a lot of time this year and I'm hoping Wisnieski is ready to step up big time. As long as this group continues to be solid, and we have a young guy as our big play/separation WR, should be solid. Kittles is a very good receiving TE, and don't forget Outsey who seems to be a really good receiving TE because his is on the field a lot. I believe that Wiz will be that big blocking TE we need and love.
RB - Love Canzeri, but I don't think it will be that big of a hole to replace. I think losing Plewa and Cox are huge losses. We saw at times last year what happened when we didn't have at least a really solid FB lead blocking and both guys have been fantastic for us. Need someone to fill that void, even if it's not at the same high level, and Daniels/Wadley/Mitchell will have no problems. I think they will go with a 2 headed monster at FB next year with Kelly (who is a beast and will be a good blocker) and Kulick, (who needs another 5-10lbs but gives them the best receiving FB the've had in a long time). I don't see a huge dropoff there.
QB - Don't think we'll have any issues here. Maybe just hopefully we can get Wiegers some more garbage time experience. Hopefully in each of the next 7 games (yup I went there) but I'll be OK with getting him some reps up 40 in on 11/14 and 11/27.
P/K - Both guys have really come on strong and are assets. Going to be tough to replace, and at this point it's a crapshoot what next year will be like.
