PAP will certainly not change for the better on everything. Or fence sitters would think more opposition resulted in the positive changes and will vote more opposition. PAP thinks it has to strike a balance and the solution is to improve the policies but harshen the political environment.
Its political approach did not improve but got worse. Immediately after 2011 it tightened the screws on opposition wards like it has never done before. Confiscation of lands, AIM, MND etc. PAP plans ahead in a lot of things, so this was long planned. What it didn't expect was there are 2 by elections after that.
Internet regulations also got tighter. The mainstream media remains the same. Several whitewashing of Hong Lim protests and protestors which they would have left alone pre-2011. Suing a blogger is unprecedented when it used to go after only opposition politicians.
On the other hand, the only positive policy effect in favour of the PAP is falling housing prices. Even that won't please those who bought their resale flats in 2009-2011 period and now suffered a loss of 10% of their property. So they can't win all the votes from resale buyers.
As for those going for the cheaper new flats, problem is, whatever problems caused by Mah cooled down only in 2013. By 2016 election, many new flats are still building while its buyers are putting up with high rents, married but living separately or postponing marriage. So they can't get all the votes from this group either unless they can find some way to postpone election until 2018 (not allowed under the law).
Losing more seats is on the wall for the PAP.
You know, the PAP knows it. It is only trying not to lose more than one GRC on top of Aljunied. PAP knows just by retaining the present 80 seats is a bonus and winning back all 7 opposition seats is a foregone dream. What PAP hopes to avoid is lose a 2/3rds majority which PAP believes is possible, or even lose power which is remotely possible.
If there was any chance PAP can reverse the situation and scale back on its losses, it would be 2021 election. PAP knows this.