Three things have struck me so far, a car when I was five, but that does not count
The fact that tax rises by May and Co could be back on the table, something one feels like them saying " well, we are in an unassailable position so lets just tear up our previous promises we had and go for it, we might lose a few but we should still win"
" We will give you 4 more public holidays" sounds like desperation.
Back to the tax rise issues, I do understand why they may be forced into that position though, when "Just Call Me Dave" was in power and the promise was made, the UK was in a stable long term relationship with Europe, and everything was ticking along rosy.
Now with Brexit, they obviously realise there may be some severe turbulence ahead on the UK PLC finances that will need to be addressed, hopefully in the short term...no one knows, so it would be foolhardy to tie one-selves down to a promise they may not be able to keep.
Labours failing was when the MPs' lost the ability to choose a leader from amongst themselves and let the party decide.