Upgrade from TW Acustic Raven AC-3 to what?

Lewm, on the "billiard analogy" ALL other factors (level, felt/fabric, size etc.) are the very same - the only difference being the mass underneath the felt. Be it slate, granite or (seldom...) other hard stone. Check out billiard tables - the huge difference in prices of different models by the same manufacturer is direct related to mass (mass underneath the felt...) and usually the published thickness of the stone platter underneath the felt is the "price factor" per se.
So - lets just predict that it is the larger mass only which makes the difference (and this too is the technical fact..).
The larger the difference in mass between two singular bodies - one (the smaller) moving on the other - the less energy is absorbed/withdrawn from the smaller moving mass by the larger mass underneath. Resulting in more inherent energy "staying" with the moving corpus and is used for movement = longer distance running.
In billiard - which I was into in my youth - this is common sense and knowledge. At least in Snooker and Karambolage - not sure about Pool....

So - let just take that fact for granted.
Of course the inner damping of the platter does add to the overall result, as does the clever sequence of different speed of sonic distribution in different materials, but the total mass has a paramount impact.
Take the platter of the vintage Basis Debut Gold.
Its not that heavy (but still above 20 lbs I think) and it is very well damped despite its vacuum suction.
However, its lower bass performance - while being very good - can NOT compete with the low register performance of platters twice its weight.
I too wished it would be otherwise.
My new turntable thus features a very complex platter with a total weight of 135 lbs (static net weight ...... but there will be 2 inertia units going with it.... so the dynamic mass will be , well - immense).
Not because I like heavy cylinders, but because I know what I need to do to achieve what I want.
The drive system does make a difference, but to a much lesser extend that widely assumed.
It does make a sometimes huge difference with poor (cheap) motors and/or light platters.
I already had a great argument with the idler-drive and direct drive fraction here on Audiogon some months back.
I know why I use the drive I am using and I am getting the results I wanted and which others won't believe.
For the model set up in my earlier post there is only one thing that matters - brute mass.
The other points mentioned do matter too - and a few more.
Enjoy the journey,
D.

Dertonearm, I am thoroughly enjoying this discussion, and I do thank you for your patience with my recalcitrance. I feel like this is a Socratic search for truth, not an argument. So.... you wrote, "The larger the difference in mass between two singular bodies - one (the smaller) moving on the other - the less energy is absorbed/withdrawn from the smaller moving mass by the larger mass underneath." I think this statement is incorrect for a ball rolling on a flat inert surface, provided it is a given that the surface does not deform due to the pure weight of the ball. (We could agree that a ball won't roll very far in mud.)

I know your conclusion re what type of tt is best is based on extensive listening and even more extensive trial and error experiments that I cannot come near to replicating. So I would not dare say you are wrong in that regard. I am just commenting on the why of it.

Dear Lewm, this is all a matter of the conservation of energy. The rolling billiard ball is just an analogy to illustrate (roughly..) the behavior of two masses in contact with each other and with VERY different individual masses and the smaller mass (stylus) in movement on the surface of the larger mass. What I am trying to do is to illustrate that point and I must apologize, as I am apparently not very successful.
Sorry about that.
In any case maybe soon some seasoned members will join us here and tell me how wrong I am and that I have no clue of a) physics and b) turntables.
So best to do for us all may be to just forget my model and that funny idea with the billiard table and that nonsense about conservation of energy and carry on as before.
Enjoy the journey,
D.

As I understood you are finished with billiard playing, so let´s spend one more thought on audiophile opinions.

A good definition is: The difference between fact and opinion is that a fact is something that is empirically true and can be supported by evidence while an opinion is a belief that may or may not be backed up with some type of evidence. An opinion is normally a subjective statement that can be the result of an individual interpretation of a fact.

I hope we agree that we discuss more or less on the bases of opinions and not all the time on facts?

Assessing the quality of TTs we may judge on some performance data, the kind of technology which is used, the acceptance of the audiophile forum (we all), the activities of the sales forces behind the product, maybe pricing as well (?) etc. In the end we select favorites which mirror the momentary level of our systems. In this stage our opinion about the brand and the type of TT is formed.

To assess audiophile opinions we have to have a close look at the experience of the opinion makers, maybe at their systems and at the quality of their recommendations. This is the kind of erratic approach we are following usually in this wonderful journey. But in some way it is following an interative path of experiences - with positive results.

When it comes to listening I do think that maybe 99,5% among us feel like an audiophile expert being able assessing TTs. Of course we hear the difference of TTs, tonearms and cartridges. We go to fairs, we visit friends with good systems, sometimes we are invited by manufactures to assess prototypes etc. In the end we usually end up defending our grounds more or less stating so called facts (which are sometimes opinions). That´s the difficult side of opinions.

Thuchan, you are so right. In the end all of us, except for Dertonearm who was in the business of turntable R&D, have opinions based on very narrow experience. That's possibly why it is of interest to consider the physical principles involved in the playing of an LP. Maybe science would take us closer to the highest form of the art. Anyway, it's fun.

DT, Yes, the energy must be conserved according to Newtonian Mechanics, but I believe it is dissipated as or converted to heat, as the cue ball rolls across the felt surface. The two masses (ball and table) are passive actors in this process; the bigger mass of the heavier slate would if anything more readily dissipate the energy in the ball than would a smaller mass of slate, or so it seems to me. I don't mean to preach; this is just me thinking out loud. I am waiting for my physics professor to correct me.