I own both JNPG and TGC, having purchased them last year to try them out before investing in the sim version of one of them to use with my SkyTrak launch monitor. After playing both games on my PC, I decided that JNPG had more realistic gameplay and higher quality courses so I now play only JNPG. I found very few courses in TGC that were of high enough quality or realistic length (with a lack of multiple tees) for a short-hitting senior like me. I also absolutely hate over-the-top, tricked up courses that are not like real golf, and TGC is loaded with poorly built courses like that. Some of the problems with TGC courses are also likely the result of the limitations in the course design software in TGC, so the upgraded course design software in TGC2 could make it more appealing for someone like me.
However, I now have developed a much more negative opinion of TGC as a result of being treated inappropriately by the administrators of a golf sim website that has a financial relationship with TGC. This is a website that provides a lot of useful info about SkyTrak and other launch monitors, but my attempts at posting questions or comments are now listed as "unapproved" by the admins. I have repeatedly sent personal emails to the admins to ask why my posts are being rejected, but they have never responded to my questions. I have never been disrespectful or inappropriate in any of my posts, but I have voiced my opinion that JNPG is a better choice than TGC for sim play on the SkyTrak. I can only assume that my opinions are not considered acceptable on a website that functions as a marketing tool for TGC.
For these reasons, TGC2 would have to be a dramatically better golf game than JNPG to tempt me at all to invest in TGC2.