I don't think they intended trials to be played indefinitely. Just as I'm certain they'd prefer veteran trials to subscribe. It's not described as a f2p option.
Your approach to trial, the same as most on this forum myself included, is playing trial as f2p. That is not Blizzard's intention and if considered at all is likely something this change is aimed at reversing. Trial as a try-out before buying, not a holding pen for f2p. Mind, I'm not criticizing trial twinkers (I've been one myself and don't find the game worth paying for). I doubt seriously that they are catering to chronic trial players, which is what you're suggesting. They want you to subscribe.
This post if for you too I suppose Robo. Trial is trial, and neither is f2p.