I do believe most data collected so far shows all secondaries contributing about 1/3 of the stat weight they had pre heavensward. (assuming lvl 60)
So roughly 3x more of a sub-stat is required than before to achieve the same 1% increase.

This will probably be more relevant in a day when we have esoteric gear implemented alongside alex savage, so that there are actually gear choices.

I do fear though that sub stat relevancy is being lost with such minimal stat contributions.
Without gear having absurd amounts of sub stats, or having much higher ilvl scaling as we go forward in heavensward.