I think populations were declining before the update. I attributed that decline primarily to the economy and people having less spending money although I do not know that. Obviously, there were people who never liked the old engine or who just never cared for GD after trying it. GD had a small but loyal customer base for what I consider to be a niche type market product.
It is no surprise that numbers increased with all the free seasons given away. It is no surprise that some of those coaches playing free seasons did not want to continue. I think those statements would be true regardless of how good the update is.
Now that the deadline to use a free season is expiring, and many old coaches are coming to the end of their free seasons, we will see how successful the update is from a business standpoint. Since many of the seasons played thus far under the new engine are/were free or previously purchased, we do not know how GD is doing for WIS from a revenue standpoint. I think WIS saw declining numbers and legitimate problems with the old engine and made a good faith attempt to address those concerns. Whether WIS succeeded has been discussed ad nauseum.
The real question now is whether GD will have enough customers to and increased revenue (or any increased revenue) to call the engine a success from a financial standpoint. I think we will start to see some answers in the next 30-60 days. If WIS starts offering more free seasons and discounts, and population numbers are declining, we will have our answer. If the new engine is not a financial success, how many coaches will be willing to give GD another chance through another engine update? Will coaches be willing to offer suggestions to WIS, and would WIS listen to them anyway? Will WIS beta test the next engine properly? If WIS learns anything, I hope it is "DO NOT RELEASE A NEW ENGINE WITHOUT PROPER BETA TESTING!!!"
I hope GD survives. They had a good product, and the willingness of most coaches to offer help and free advice to those who wanted to learn was essential to my success and helped make the game as enjoyable.