It is not so slow, but with relatively large block time (15 minutes) and hashrate dropping to 10% it means the expected block time raises to 150 minutes.
Only 10 block have been mined with PoW since the nfactor increase, and due to random nature of the mining (sometimes you need to do 400% of expected hashes to find a block sometimes if you are really lucky you get a block under 1%) there is a limit in how fast you can adjust the stuff to avoid overadjusting (like setting 100x higher difficulty when seeing that "1%" block) and how far in the past you have to look for the statistics.

Also, as people will fix and retune their mining rigs, the hashrate should gradually increase to about 40-50% of previous value.

And if you look here: http://cach.catcoin.cz/index.php?page=statistics&action=blocks
You can see that this pool had very good luck with last 4 blocks (got them in time that would otherwise yield only 1 block in average), so with this luck (pool getting 4 out of 7 last PoW blocks) the diff have not dropped as much as it would without it (with only the average luck the pool would have taken only 1 block out of 4, with bad luck 0 out of 3 ..)

I guess that good luck just ran out (now at 77.82% of expected shares and still nothing, although there is still chance to find next block before the expected time , so I guess the diff will start dropping much more quickly in the next few blocks