Golfpin
I think, it is beneficial, to (try to) understand what the "idea" behind a suggested setup is. I know that you try to do so, because you come here and ask the question. Just because some "well known" motorsport figure says something, doesn't mean, that it is the "be all/end all", because there is still a fair bit of "monkey see - monkey do" going on in the motor racing world, all the way up to F1.
Furthermore, I think it is worthwhile to keep in mind, that a lot of motorsport "engineering" decisions are (at least partly) "rule driven" and not necessarily "driven by engineering/first principles". In a nutshell, that means, you have to make your car/bike as fast as possible on the day, with what you got, and at times, that may includes things, that "fly in the face" of "normal engineering practice".
One case would be, that many (almost any) championship today has you run a mandated tyre. Now, you would hope, that this tyre is well suited for the application at hand, but I wouldn't bet the farm on this. In "lower" spec series ( and this can include national championships in some countries), it's quite often a "price driven" decision. So the manufacturer,who provides the tyres, may just uses what he "still has on the shelf" (from a discontinued other championship &/or stillborn series)instead of developing a tyre for the application at hand. In such a situation, and I have worked in such a championship, it's not always beneficial or better to have "four tyres on the ground". It can be a case of "he - who has the most load transfer wins", literally trying to get your car on "two wheels" in every corner.
That doesn't make a lot of sense, but if you consider that a slick tyre needs a minimum energy going through it to "switch on", things can change.
So, don't assume anything, if you don't have to - often there is more to it, then meets the eye. - with apologize, don't mean to sound like a smarta.... - but "be careful" with some broad/wide sweeping statements like this.
Golfpin said:
surely with what we know to day, not good. 4 wheels on the ground must be better than three!!!!!
See "coil binding" setups in NASCAR for another example. All these things may not being the "most elegant" solutions - engineering wise, but this brings us back to a "rule driven" statement, I made earlier. Just that something "doesn't make sense on first glance", doesn't mean, that it can't work, if you consider ALL things, which may come into play.
but coming back to your initial question, people do this stuff (zero droop / droop limited suspension) for different reasons.
if you find an Formula Ford team/racer, chances are, that he will know some things about it ( at least changes are high, that he uses such a setup). Because it is a very common FF setup (other single seaters too - but for an aero car, not everything, that "looks like" a zero droop setup on the setup patch (at no speed/no downforce) is a "zero droop" setup while driving on the track (airspeed --> downforce).
One thing worth to remember, in the FF context is, that and FF has an open diff, so to achieve good "power down" you will try to keep as much load on the inner tyre as you can. It think, we will all agree, that if you start lifting a wheel off the ground, you have achieved the maximum contribution of this axle (the one who will lift a wheel), in terms of it's contribution to overall roll stiffness.
Therefore, you can't "ask" more (roll stiffness) from this axle.
Other "typical" examples would include "older" Porsches (911), who used (and some still do) droop limited setups at the front, and I'm sure you will have seen Porsches lifting the inner front wheel on corner exit. This may ties in, with what Dynatune said about the effect of weight distribution on handling.
Which brings us/me to the final point I would like to make, you should look at "zero droop" setups not only in terms of "pure" lateral acceleration, but also in terms of "combined" (lat & long) acceleration. Chances are, that you will brake before entering most corners, and perhaps "trail" some brake (longitudinal acceleration/deceleration) all the way to the apex. In this conditions (nose/front down - pitched) you may have not "zero droop" anymore, but this may changes when you start "powering out" of an corner.
So, you could see this (and similar techniques) as an way/attempt to manipulate roll stiffness distribution as a function of longitudinal acceleration.
Other things to consider (especially but not exclusively for aero depending cars) are that if you don't have "pure roll" (pure roll = the outside raises as much as the inside compresses - CoG position remains constant), you will have a change in CoG position (a heave component in addition to the roll component), this in turn, can/will have a couple of effects ranging from kinematics (camber gain/loss etc.), over general load transfer - CoG height affects overall load transfer, to aero effects front wing/splitter/floor height with respect to the ground etc. etc.
So as you can see, and I have just touch on some of the stuff, there can be various reasons, why one may considers/favors a "zero drop/droop limited" setup. And as always, there are many ways to skin a cat, this type of setup is just one meaning to a/one specific end/aim - there are surely others.