Well they’d have to get rid of the unbirthday thing as well. that is a good one for CF spam
They did get rid of that in SAAB but added a bunch of even more exploitable recurring quests - namely the ones where you can do a fight and then abort it and do it again - you don't get rewards but you get the ranking points, fight count, and pvp tower points (come to think that was probably what the PVP Arena idea was trying to mask while getting rid of the towers, crazy tower scores in SAAB because they'd always rather mask a problem than address it.)
Someone actually did the math, one abuser on our server was getting over 600 fights per hour or something like that, more than 10 per minute. Still others can go ahead and actually complete the quest legitimately a few times per day for actual rewards, more like it's meant to be used. You actually have to trade some goods or win 6-12 fights to complete the other battle based recurring quests. Let's not leave out spend 150 fps and spend 200 fps in SAAB, which everyone can hit a few times a day just taking 1.9 spots on GB's.
Other's have made great points about better solutions - cap the number of times it can be repeated per hour/day/week (how much is abuse? 50 times? 100? pick a number!), but that requires more programming than simply making everyone wait an extra 2 seconds. A delay does nothing to the actual abusers it's aimed at, those somehow doing hundreds of fights or rewards per day through the loop quests will carry on with slightly less infinite quest rewards, but the delay annoys everyone who wasn't doing that.