One possible way to solve the PoW block time too long issue is to decrease the max allowed PoW block time, which is currently set at 12X normal time. This means due to the generation of PoS blocks, the PoW block time can be extended to 12X normal time (of course when PoS generation decreases, the PoW block time will decrease and go back to target time). The PoW target time extension is needed in order to maintain the overall block target time.
We could decrease the max allowed PoW block to 3X normal time. Actually I noticed that Novacoin did this patch many months after they launched the coin. We could do the same. This will make the delay of the PoW less significant. However, this will require another hard fork, which is why I am reluctant to do. If the community thinks this is needed, I can make the changes.
Again, the PoS issues I discussed before the release of Version 1.3. Please refer to it (link below) and understand the pros and cons of the PoS blocks.
https://bitcointalk.org/index.php?topic=361503.msg4419112#msg4419112I think the fair value for POW block time extender would be 1X. But if, 3X is the down limit, we should go 4X, to have difference. But this info should be stated in OP/official site.