I think tweaking the sbd bank to take steem as well would be a worthwhile option to explore. Call it Steem Power Lite if you will.
I don't think there is a particular rush to move powerdowns to 4 weeks. We have no data to support this will help SMTs because those are a long term investment even compared to 13 weeks. So holding it until a year or so later if the prices don't increase is another option.
I just have a feeling that lowering it to 4 weeks will turn Steem more into a speculative asset. There are hundreds of other cryptocurrencies doing this already.