All our existing FSX airports are usable in P3D 4.2 FOR FREE, you haven't been asked a penny to upgrade for them, and in some cases, they were originally released for FS9, which means there might be users that were able to jump with their FSDT scenery from FS9 to FSX
for free, and again from FSX to P3D2, 3 and 4,
for free.
So, the first part of your message should probably say something like "Thanks for FSDT, which is allowing me to use a scenery purchased in 2007/2009 (like Zurich or JFK, for example), and use it through 3 generations of simulators, without having to pay anything"
Having said that, it's just wrong to generalize, because there's a big difference between the airports.
Not all of them have "ridiculously low framerates" ( and they ALL have very good fps with more fps-friendly airplanes ), the ones which only had at least native FSX code (no FS9/FS8 code), are still performing well in P3D4, and this means everything released after 2010 so, KDFW, KLAX, CYVR and KIAH.
See the attached screenshots, which shows the supposedly "oudated" FSDT KLAX and KDFW, compared to the Aerosoft Frankfurt Professional 2.0, which is advertised as a NATIVE P3D4 scenery. Yet KDFW and KLAX are both outperforming it, using the exact same settings.
Most of the issues are likely coming from the earliest ones, which were still made in the FS9 era when FSX wasn't fully established, like Zurich, Geneva, KLAS, KFLL and the Hawaii airports. KJFK has been updated in 2013 so, at least it's fully FSX code, so is still performing adequately, even if it looks a bit dated now.
The latest 3 we released, KMEM, KCLT and KSDF, have been designed taking into account P3D mostly, and they work FAR better in P3D4 than they ever did in FSX. But they are still designed to be compatible with FSX so, they are not using P3D4 to its fullest extent because, in order to do that, a scenery should be designed from scratch and NOT be compatible with FSX anymore.
We are doing this for the upcoming new O'Hare scenery, which has been discussed quite extensively in other threads:
http://www.fsdreamteam.com/forum/index.php/topic,17447.0.htmlAnd yes, this will be a new purchase, but still with some way of discount for previous owners.
So, clearly, after O'Hare, we'll remake the other older sceneries, starting with the ones which have been most requested, like JFK and KLAX. But it's not as if that, just because you said you are prepared to pay, we can release them "instantly".
By demanding more quality, you must also be prepared to wait more, because it's not possible to create a scenery with the quality you are asking for in only 6-9 months, as it used to be, unless you are doing only tiny airports.
So yes, of course we'll eventually remake all our most important airports, and we are starting with O'Hare, because it was not just old, but also outdated, but this will take some time.
