Leaving aside the welfare issue, I agree completely that further reform in the public sector is needed, but people need to be aware of the consequence of tearing up the Croke Park agreement - it would effectively be the end of social partnership.
I'm still the right side of 30 and not politically interested TBH, but my older colleagues in the PS tell me that social partnership effectively sidelined the unions, relative to how things were back in the 70's & 80's.
So if you tear up social partnership, an inevitable consequence will be an even higher level of union activism, more industrial actions, strikes etc... and the creation of a hostile environment where it could become very difficult to implement change.
There would also be a knock on economic effect; presently public sector workers may feel they have some degree of stability (under the CPA). If this is taken away, and wages cut further, with no certainty about whether there'll be yet more cuts still to come, then you'll have another class of people who will stop spending money in the economy and plough all their disposable income into savings... that's more jobs lost in the private sector.
Costs vs benefits... not always as simple to weigh up as you might hope.