There really isn't much to see here. Ubuntu has a simple choice. They either rev the kernel as an SRU to their 13.04 release or they commit to supporting the existing kernel for the stated release lifetime for their non-lts 13.04 release. That's it, that's the options.
Making the choice they made here is the more conservative choice of the options available to them and is inline with their historic policy on trying really hard not to introduce large changes into the core system as part of the SRU process.
It's a noteworthy announcement for users of 13.04, but I'm really not sure there's much here worth discussion here.