Well, on the margin is makes finding a block take marginally longer (is my understanding). So over looong periods of time, it would lead to marginal difference

Well, on the margin is makes finding a block take marginally longer (is my understanding). So over looong periods of time, it would lead to marginal differences in outstanding blocks. But with the resets in the difficulty (to target ~10min block time, again I could be wrong) every two weeks, it's not really an issue. On the other hand, it should increase the profitability of mining for those left in the game, who are X% more likely to get a block with the rest of the network down.