I believe it matters more to the Watchtower organization that JWs believe a certain way than it does to the average Christian, who has freedom of thought, as to what hope they entertain in regards an eternal future.
However that said, many of the JW prooftexts for paradise earth are flimsy and a result of eisegesis, rather than exegesis. When one looks at the context, considers what the writer originally met and their mindset, it does not prove Watchtower interpretation.
For instance, in the original languages, the word some translations have for ‘earth’ basically means ‘land’. It can also mean ‘soil’, depending on the context. Did the writer mean ‘earth’ as in the planet as we conceive it? It seems unlikely.
Take Psalm 37:29…it can easily be translated as one translation does: “The righteous will inherit the land and dwell in it permanently.” The word translated as ‘forever’ is olam, which really means an indefinite period of time. Is the passage and context talking about the eternal hope of individuals? Or is it rather talking about the righteous as a class?
Similarly, passages such as Isaiah 65, when viewed in context, are clearly about Judah and Jerusalem and the return from Exile and speaks about it in poetic language. In the passage, people still die of old age! The Watchtower does acknowledge this in the publications, but they talk about an “initial fulfillment” and a second, and sometimes third fulfillment. But where is the evidence for additional fulfillments?
It really comes down to interpretation of Bible texts. But whenever someone presents ‘prooftexts’, a person needs to ask if the interpretation of these is exegesis or eisegesis.