Walter Montego:
The Marshall is a powerful piece, I agree.
We also agree that its use occurs later in the game.
If we compare the dynamism of the two Janus with the Marshall and Cardinal, we can accept that the start of a Janus game is much more fun.

As regards the Chinese Cannons (by the way have you already had time to read the rules of Chinese Chess?).

My intention is not to accumulate powerful pieces like with Rooks but to add two very interesting and exciting pieces full of new combinations possibilities.

I see no reason why Chinese Cannons are not yet used outside the Chinese Chess. Probably simply because it is unknown is a reasonable explanation.

Actually, all occidental pieces are formed from an association of Bishop, Rook and Knight movements. Why not extend that with a so tricky piece?
I am certain it will give a new breath to our play.

I ignore the Ultima game. Where, please, can I read something about?