Only slot in Rashas if you face a lot of artifacts. Try swapping out 1 star’s fury and 1 dioltas/ nimbus for 2 rasha’s. Rasha’s is a very situational card, adding 2 in is just for consistency’s sake. If you wna be more risky, you could try just cutting out 1 star’s fury for 1 Rasha’s. As for cutting out star’s fury and Nimbus/ diotals. Star’s fury is also a situational card. It is able to fish out lethal if your opponent swarms the board or have a decent board with a few minions. If they do spend the mana to play an artifact, it means the board wont be as strong as compared to when they choose to spend the mana pused for the artifact into developing minions. Hence, making a star’s fury one-off if you’re going aginst more artifacts makes more sense.
For better consistency, always put in 2-off’s, unless it’s like a super tech card for a very specific situation like Crossbones for mechazor. Rasha’s is quite versatile but just doesnt do quite enough on its own except for artifact breaking. So it would be okay to run 1-off’s for those 1 in 10 matches where you need to break let’s say an arclyte regalia or spectral blade. But do run 2 of them and give up the greedy cards if you run into like maybe 4-5/10 matches, cause rasha’s wins you games tbh; by making your opponent fall further behind on health and board by playing an artifact for just a 2 cost spell.
As for Dioltas/ Nimbus. It really is up to you here. Dioltas is on paper better to keep as 3 off’s because 4 drops are very important in this game. Also that Dioltas has more aggressive stats to close out games faster and worst case scenario, has a 10 health tombstone (provoke) to stall out. Nimbus on the other hand is ultra slow. But it definitely is stronger than a Dioltas even if it gets dispelled. It is an inherent 3-8. It’s game losing if untouched by the opponent for more than 1 turn. Worst case scenario, it eats up a removal; allowing you to drop your other threats (Dioltas, Aymara, other nimbus) more safely.
TLDR: Drop 1 star’s for 1 rasha’s for a riskir approach. Drop 1 more dioltas or a nimbus for a 2nd Rasha’s. Drop Nimbus for a more midgame, aggressive appraoch. Drop Dioltas for a more end game approach.