Is it a matter of skill or a matter or perceived randomness?
I would ask that same question about nightriders, but they seem popular anyway. If I'm understanding you, the problem with Jokers is that they're too easy to exchange favorably because they're much stronger at the start than the end. I would expect that to be less of a problem with a very large game, since both players would have more opportunities to use their jokers.
If you're using it in a different armies game, the most important thing would be to have a joker in every army. Do you have an interactive diagram to show an example of a game where this piece might not work?
I would ask that same question about nightriders, but they seem popular anyway. If I'm understanding you, the problem with Jokers is that they're too easy to exchange favorably because they're much stronger at the start than the end. I would expect that to be less of a problem with a very large game, since both players would have more opportunities to use their jokers.
If you're using it in a different armies game, the most important thing would be to have a joker in every army. Do you have an interactive diagram to show an example of a game where this piece might not work?