5E - making static spells more active?

From Trollsmyth's blog.

Quote:

Originally Posted by Trollsmyth Check out this bit from the spell flesh to stone (page 243 for those of you playing along at home): A creature restrained by this spell must make another Constitution saving throw at the end of each of its turns. If it successfully saves against this spell three times, the spell ends. If it fails its save three times, it is turned to stone… Yep, turning someone to stone is no longer a quick, save-or-die roll. I think all the old save-or-die spells have been changed this way. Mearls said he wanted to end the anticlimax of facing down the ancient dragon in its lair, only to have it fail a save in the first moment of combat and end the fight right there. I’m not sure how much I agree with that goal, but it certainly makes those spells a lot more exciting and dramatic in combat.

I think this is an interesting mechanic for a save-or-something kinds of spells especially when the target of the spell is either a PC or a significant adversary. Allowing the target a chance to fight off the effect of the spell keeps the player(s) interested in the spell effect beyond the single round of casting. I will also be looking to see where I can use this idea for other games.

5E - making static spells more active?