"widely discussed topic" is correct and usable in written English.
You can use it in a variety of contexts. For example: "Climate change is a widely discussed topic, but the solutions remain elusive."
Let's not kid ourselves, as Mark Brown writes, the most widely discussed topic of all has been the inhospitable weather.
The safety of New York streets has been a widely discussed topic of late — in conversations both bracing and absurd.
A widely discussed topic at the Bangkok conference was the development of microbicides in the form of gels, creams, or other substances that could be applied vaginally to reduce the risk of the transmission of HIV and other sexually transmitted infections.
JPEG2000 encryption has become a widely discussed topic and quite a number of contributions have been made.
In the last few years QFT has become a more widely discussed topic in philosophy of science, with questions ranging from methodology and semantics to ontology.
Mental health among college athletes is starting to become a widely discussed topic.
Throughout 2014, the internet of things (IoT) was undeniably one of the most popular and widely discussed topics in our industry.
The rapidly increasing cost of higher education is one of the most widely discussed topics in the country, especially among current and perspective college students and their families.
6 Frailty is a widely discussed subject in developed countries and many studies have been published on this topic.
This counter gives you an idea of how widely discussed the topic is on the Facebook network.
The origin and maintenance of sexual reproduction is a controversially discussed topic in evolutionary biology as reflected by the multitude of theories that have been proposed to explain why sexual reproduction, although highly costly, is widely occurring in nature [ 1- 6].
