Looking at WI voting patterns, it seems that there pretty much have to be three Democratic districts in the state: one in Milwaukee, one in Madison, and one along the western border with Minnesota. But if the GOP wanted to be really nasty, they could pack Madison in with the heavily Democratic regions along the Western border into one super-democratic district and allowing them to take over all the other districts in the state. This map accomplishes a pretty solid 6-2 split in the WI delegation for the GOP, while simultaneously strengthening the districts of reps Ryan, Duffy, and Ribble.
The Democratic vote dump in the 2nd connects Madison, La Crosse, the counties just south of Duluth, and some other highly Democratic counties in the SW region, forcing reps Kind and Baldwin into one district. I would have added in Ashland Co, but rep Duffy lives there (reps Duffy and Ryan are both in the unfortunate situation of living in the most democratic areas of their districts, interestingly). Rep Ryan's 1st is probably shifted the most to the right of any district in this map, due to his seniority in the house. It loses the Dem-leaning areas of Racine and Kenosha, and gains a lot of more rural territory. Some of this territory in the SW corner of the state is ancestrally Democratic (although it voted mainly GOP this year), but the rest of the area is very conservative, which has the effect of giving Ryan a pretty safe seat for as long as he wants it. Ryan seemed to have a lock on his old seat, but if the GOP is smart they'll probably try to make it safer; his old district was won by Obama in 08 (although some of that may have been due to the fact that WI-01 borders Illinois and contains areas like Racine and Kenosha that are suburbs of Chicago). Perhaps more importantly, Ryan is actually incredibly conservative for a swing district like his, this analysis by Crisitunity back in 2009 found him to be the house GOPer in the 110th congress most to the right of his district (the GOP version of Nate Silver's Most Valuable Democrat, if you will). This seems to suggest that in the future Ryan could be vulnerable in his current district, although he hasn't shown any signs of it yet. Anyway, under this map, he probably wouldn't be vulnerable anymore. Racine and Kenosha are moved to the 5th and 6th, respectively. Those districts have moved slightly to the left to help other districts, but they are still solidly GOP districts anchored in very conservative territory. The 4th in Milwaukee has gotten slightly more Democratic, and is now majority-minority (47% W, 33% B, 15% H), which helps the surrounding districts a little. The 8th is changed a little in partisanship; it has lost some light red areas in the NE corner of the state for deep red areas around Manitowoc and Sheboygan. The 3rd now stretches east from Eau Claire to Oshkosh. It is probably the most Democratic of all the districts other than the 2nd and 4th. And finally the 7th has now lost the most Democratic parts of the district is now much safer for rep Duffy.
The upper midwest has generally had very little history for gerrymandering in the past, so there could be a good deal of political fallout for the GOP if they decide to push a plan like this. They might be able to get away with chunking the south of Duluth counties into the 3rd, but something like this, although not terrible by the standards of states like CA, MD, or TX, would be the worst gerrymander WI has seen in ages.
