Because of the 50/50 split between Labour and the others, my favoured coalition - that of a rainbow is now a no brainer. A minority Labour Government might (just) work, a minority rainbow coalition would be an impossibility.
Even if it was a possibility, I'm not sure that I would still back any form of coalition in either a First Past the Post or FPTP plus election, the risks of coalition are too high without the protection of a proper (STV type) proportional vote system.
Plaid Cymru's mantra since 2007 has been that the party has given added value to the Labour led government and stifled some of its excesses; the Lib Dems have made a similar claim about their influence on the Tories in Westminster since 2010. Both narratives are probably true; but neither party has benefited from it.
The problem seems to be that if you like what the Labour / Conservative led coalition governments have done you vote Labour / Tory rather than Plaid / LD. If you don't like what the Labour / Conservative led coalition governments have done you vote against their coalition partners who have enabled them to govern – a lose/lose situation.
There have been rumours that the Lib Dems are considering an agreement with Labour in the Assembly. That would be suicidally stupid! Giving the benefit of their input to two different parties and receiving the blame for the failures of both.
In a funny sort of way Plaid might be in the best possible position, if it resists both a Coalition or a Supply & Confidence agreement with Labour.
There are things that a Welsh Labour Government will want to do that the ConDem Westminster Government won't want them to do. Plaid is in a position to trade its support by squeezing a bit of blood from both sides!