The consideration given is that, unlike the original proposal, this one doesn't double the blocksize. It's a measured and more conservative increase, which will allow nodes to keep pace, which is what you want. I've even stated that the 12.5% part is open to negotiation, but it is a hard cap. It means precisely that the blocksize can't increase (or decrease) by more than that amount over a period of time. The period of time in question is also negotiable. This gives you everything you're asking for, we just need to decide what the limit should be and over how long a timeframe.
12.5% YOY sounds on par with Pieter Wuille proposal. I honestly wouldn't mind it 
I've always been against making pointless predictions as we can not know what is going to happen in the future. We can't expect any fixed solution to be the right call.
Update:
Not sure where the YOY part came from, heh. That's a little too conservative for my tastes.
No idea either. I just responded to his post. I do concur.