The Reality: The fact that lifelink is a triggered ability leads to situations where the controller of a blocker with lifelink dies from combat damage before lifelink can grant that player enough life to stay alive. Many players get this interaction wrong; the subtle difference in timing is unfortunate.
The Fix: Lifelink, like deathtouch, is turning into a static ability. If a source with lifelink deals damage, its controller gains that much life as that damage is being dealt. This brings the timing much closer to spells like Consume Spirit and Lightning Helix. As a side effect, multiple instances of lifelink are no longer cumulative.