You overestimate my reputation; I am pretty sure most people playing chess variants haven't even heard of me.

Computer studies are not beyond doubt, like nothing in science ever is. But that does't mean that any voodoo method should be considered equally valid and reliable as serious scientific research. I don't know what your reservations are with respect to results from computer self-play. (After all, the level of play these can reach is often superior to that of human GMs.) But it seems to me that most other methods have very serious and obvious defects, and often are not better than educated guessing without any attempt at a ' reality check'.

Correct me if I am wrong, but it seemed to me that you concluded from the fact that the Alfil and the Dababba are practically worthless pieces that the A an D moves also hardly contribute to the value of a Champion. And that is totally flawed reasoning. Alfil and Dababba have low value because their moves fail to cooperate in a useful way, so that they can access only a small fraction of the board. Not because the individual moves were intrinsically less useful. But this can hold for any type of move, on a piece that only has a few of them. I already pointed out that a (say right-handed) Half-Knight is worse than a dababba in this respect. And replacing the sideway jumps of a Dababba by the vertical moves of a Wazir makes the piece even weaker (as it is then confined to a single file).

You can always think of a piece as a compound of a number of pieces with fewer moves, and the latter can be given so few moves that they are practically useless. Trying to correct that by arbitrarily adding a Pawn's value each time you combine two of them, because that seemed to work for a Queen, is no good and leads to totally wrong results: it would estimate a piece that has two diametrically opposite Knight moves as at least 1P,  the combiation of two of those moving along perpendicular hippogonals (the already mentioned Half-Knight) as >3P and a full Knight at >7P.

To have a method of piece-value prediction (as opposed to measurement) that makes any sense, one should take account of the fact that moves must cooperate, and that some specific combinations of moves fail to do so in a useful way, leading to some severe ineptness of the resulting piece (like color binding or lack of speed), which cannot be blamed on any of its moves in particular. E.g. a Camel is a very weak piece on 8x8 because it only has moves with long stride, forcing it to a useless and vulnerable location when it gets chased away from a good one. (And in addition it doesn't cooperate well with other orthodox pieces, which all have short-range moves, so that there is no possibility of mutual protection.) I am not sure at all that the Wizard would suffer from the same problems even on 8x8, as the Ferz moves it also has see to fully solve that problem. The Camel moves might be just as good as any short-range move. It might fall off board more often, but it can also attack deep into the opponent's camp. Even more so on 10x10.