One of the main reasons Cuckoo cycle is atractive when compared to Cryptonight is that it is very fast to verify. This is one drawback of Cryptonight: it makes all operations that need to verify Cryptonight hashes slower.
Another reason to want a switch to Cuckoo cycle would be to keep the CPU/GPU/ASIC performance within a reasonable scale. Should ASICs pop ...
Monero Research Lab Publications MRL-0001 to MRL-0005 have been published.
MRL-0006 - Difficulty Adjustment Algorithms in Cryptocurrency Protocols
have been started.
According to fluffypony
The difficulty research that Surae was working on is quite extensive, but incomplete.
EDIT: as of November 17th, it appears MRL-0006 will be renamed MRL-0007.
The arrival of quantum computers (QC) isn't necessarily a reason to change the PoW. It would only be necessary if the first generation of quantum computers are so fast that only a small investment is required to attack the network.
That scenario would allow the first person to build / buy a QC to attack the network.
If on the other hand--and I think this ...