I highly suspect soon there will be "super GRCs" - North, South,
East, West GRCs where they start merging single constituencies and
current GRCs to form even bigger GRCs.
That will crush the opposition of any chance of getting into
parliament. 
getting into the parliament is not a big issue. Today our govt are
more enlighted, they will allow more oppositions into the
parliament, so that any policy or bill passed will be deem as a
holistic and not merely just base on PAP agreement.
Therefore, for opposition, getting into parliament is no more an
issue, but the ability to stay in there is a big issue...they may
end up being scapegoats for PAP