The common Bravos Bladedancer is okay in Kojo and probably not the thing you want with Atsardi. Kojo has other options at 1 cost, with Ratatoskr probably being primary amongst them. At common (without any other shenanigans) you are getting a 1/1/1 for 1 from hand and a 2/2/2 for 3 for reserve which is not that great. However, if we have Basira as our hero instead, we get a 2/2/2 for 1 from hand and a 4/4/4 for 3 from reserve which is above par for the cost on both sides. Of course, if the Bladedancer is paired with Physical Training or even All-in you could get a much better return from the Bladedancer from reserve, the ceiling on it would be an 9/9/9 for 3 mana from reserve if you get super lucky with your All-in and yo have a Haven already in play.
The rare Bravos Bladedancer makes you play a bit more of a game with your boost counters. Provided you have 4 or fewer boost counters when played from reserve you lose fleeting on it. I believe that you can stack effects from the play ability in any order you want (to be confirmed with the full rules booklet), so if you have 4 boost counters on it, you stack the loses fleeting first, then gain the boost from her ability, then potentially gain Haven, Bravos Bastion’s boost, then potentially gain Basira’s boost, making the Bladedancer a 7/7/7 for 3 mana with no fleeting. You then get to play her another time (if not removed or sabotaged) to create a 10/10/10 for her final fling.
The OOF rare is in Ymzir. Ymzir loves having a low cost drops to win an expedition for a low cost after having removed the opponent’s big creature. A 1 cost 1/1/1 is ideal for this and a 2/2/2 for 2 isn’t bad on the reserve side either. It will compete with Ordis Trooper as a sacrifice target for Lindiwe and Studious Disciple and Spindle Harvesters have missing stats. I think with the Seasoned ability though this is something that Arfanas desperately wants. His ability to boost when casting spells is ideal to go with the Bladedancer as those boosts are saved in reserve and can be used again for the low cost of 2 mana. I could see the Bladedancer used as a sacrifice target, but the Jellyfish is much better for this, with Ordis Trooper being a close second. Also the Ymzir Stargazer when sacrificed gives two boost which can nicely go onto a Bladedancer that will keep them in reserve.