Things are not looking good for the DPP at the county magistrate/mayoral level.
Worst case scenario would involve being completely wiped off the map. Success means holding on to their current count of three seats. Best case scenario for the DPP is winning 5 of the total 17 contested positions, picking up Yilan and Penghu.
First, keep in mind [pdf] that party I.D. tracking polls by Global Views Monthly show about 40% of voters consider themselves pan-blue leaning versus 20% who call themselves pan-green leaning. Another 35% consider themselves centrist. So, despite the current rather grim figures that the Ma administration and the KMT legislative caucus can show for their support, the DPP has a lot more work cut out for them in any election.
Second: County commissioner elections are local elections and, unsurprisingly, result hinge on local issues and individual popularity. That is why you can see overwhelming victories for candidates in some counties, with upward to 70% of the vote going to the winner; he's well known and well liked. More like a club president than a politician at that stage, really.
Third: the DPP positions in Yunlin and Chiayi county are likely threatened by the corruption charges pending against those incumbent county commissioners, who have already been renominated. Chiayi is probably a little safer. Pingtung seat could be lost if the KMT holds down the number of popular blue-leaning candidates to just one. Losing those three seats could mean the whole map is painted blue.
On the potentially positive side, The DPP's Penghu candidate, Cai Chien-hsing (蔡見興), is native to the offshore islands and was a former KMT member who went rogue and then flipped to the green side in 2004. He's been on the Kaohsiung City Council, and a personality like his may be able to win in Penghu, especially considering the KMT incumbent there did not win by much last time around.
The DPP's Ilan candidate Lin Tsong-shyan (林聰賢) is a former Luodong township chief (that's an urban township) who won by large margins. He is also an ancient rival of the current incumbent. He seems like a reasonable choice by the DPP to run and has some shot at winning a seat.
You can expect similarly abysmal results for the DPP at the city council and township chief level, where the KMT and non-partisans have dominated since the days of martial law. Here are the percentage break downs of seats won the level last time elections were held, based on CEC data:
Although redistricting will have some effect on exactly who runs and wins in what areas, we can't expect the over all numbers to change a great deal.
So, there you have it! And having taken a hard look at the numbers, I will now go cry a little bit.