The phrase "a much discussed topic" is correct and usable in written English.
It can be used to refer to a subject that has been the focus of considerable conversation or debate.
Example: "Climate change has become a much discussed topic in recent years, with many experts weighing in on the issue."
Alternatives: "a widely debated topic" or "a frequently talked-about topic".
The advent of fully automated road vehicles meaning cars that drive without the need of a human driver is currently a much discussed topic.
The so-called 'Series A gap' — that is the lack of Series A funding compared to seed — is still a much discussed topic here in Europe, and in the last few years we've seen a plethora of new funds aiming to plug that gap.
It's also a much discussed topic online.
This alarming fact, which is one of many, is primarily the reason why hand hygiene has recently become a much discussed topic.
This was a much discussed topic at Digital Music Forum West a few weeks back and a source of real concern to the music business... what would it mean if the physical business continued to decline without the growth in digital track and album sales?
AKP is a much discussed topic, but at the same time it is not unambiguously defined.
The relationship between the gene of classical (pre-molecular) genetics, and the gene of modern molecular genetics is a subtle and much discussed topic (Beurton, Falk and Rheinberger (eds).
Another much discussed topic is how repeated changes can be adequately represented.
For PBS since 1989, Smith has created 26 prime-time specials and mini-series on such hotly debated and much discussed topics as terrorism, Wall Street, Soviet perestroika, Walmart, Enron, tax evasion, educational reform, health care and Washington's power game.
Drug promiscuity and polypharmacology are much discussed topics in pharmaceutical research.
The risk of increasing frequency and duration of dry periods has become much more discussed topic with respect to expected climate change.
