I frequently visit Tikiman's site as well as folllow his posts on other sites.
He seems to have a good idea about what eventually will happen at the Poly but doesn't know the exact timing (because Disney takes great pains to keep this a secret and/or frequently changes its plans).
Some things I have sort of gathered:
1. The first change to the Volcano Pool area will be an addition of a hot tub. This may happen as early as the Sep/Oct time frame but it also may not start until the very end of the year.
2. The Volcano Pool area may be completely closed down for at least a couple of months. No idea when this may occur or whether the hot tub addition will occur prior to or during this time (although it seems very unlikely they would close the Volcano Pool at the same time the Main Courtyard Pool at GF is closed - Disney has announced that the GF Main Courtyard Pool will be closed From August 24 until "December" but hasn't provided a hard completion date).
3. A Poly DVC addition as well as major refurbishment work on the GCH is going to happen but it's anyone's guess as to when (my guess is that major changes in this regard won't happen until the GF DVC is nearly complete, but that's just a guess).
We'd like to stay at the Poly in mid-December so my wishful thinking is that the Volcano Pool will be open then and the hot tub addition will have been completed before that time. However, the fact that they didn't announce the closures at the GF until just weeks before has me very concerend that they'll do the same thing at the Poly.
For example, I'm worried they'll finish the main GF pool in early December, then close the Volcano Pool the very next day (for the rest of December and into 2013) but not announce this until, say, some time in November (well past my 45 day mark).
On the other hand, I take some comfort in thinking they wouldn't start this right before peak Holiday season but would likely wait until 2013. And, if they're going to close the Volcano Pool, it would sort of make sense to do it the same time they're working on the Hawaii (CL) buliding (scheduled to start in early 2013). Of course, this doesn't provide the OP much comfort (which is a reason the OP may wish to lean toward GF, their main pool is supposed to be finished before the end of this year).