While I don't have a problem with subscriptions, and I would gladly pay it you have to keep in mind that no all of us afford it.
I've been a member for a long time and in a period of ~10 years it was the only software I have purchased. I paid something like a week's wage for it but the ROI was incommensurable and I would gladly do it again.
Currently I have stopped using TR due to restrictions at current workplace. Unless you have administrative permissions you can't install it and this being a high security environment I can't even delete shortcuts on my desktop.
Long story short, I am investigating having TR on linux server with http output so I can access it anywhere from just a web browser.
Claire, I think you should do a survey and ask your members what they think about supporting development. I don't remember receiving any marketing emails from you guys, and I wouldn't mind seeing one in my inbox once in a decade.
Meanwhile setup some sort of direct debit, auto-payment system with various amount options for those who want, to enroll now. From what I can see now there is not even a donate option, all I can do is purchase another license which I am not sure will work being that I am using the same email address.
All in all, count me in.