Now don't kill me, but in my opinion Ashfur DID deserve to go to StarClan and here's why.
First lets start off with when he went insane. Now you all say that Ashfur killed Firestar by leading him to the foxtrap. Well youre wrong here's why: It would count as killing if Ashfur physically went and attacked Firestar, but he didnt. The foxtrap killed Firestar, not Ashfur. Hawkfrost was trying to kill Firestar by tightening the rope on the foxtrap, that counts as physically killing. Now, it was kind of Brambleclaw's fault because instead of being a loyal and proper deputy, he let's Hawkfrost cross Thunderclan territory because Hawkfrost was his brother. Anyways I'm talking about Ashfur, not Brambleclaw. When Ashfur trapped Squirrelflight and the three in a fire, he didnt kill them, so that's one point why Ashfur went to StarClan. All Ashy did was threaten to burn them, he didnt really do it. Now, Ashfur had no one to support him, his father was most likely dead, Brindleface died, his other siblings died when he was a kit, and his sister Ferncloud is in the nursery with her kits. He had no-one.Squirrelflight was his last chance for happiness, but when she rejected him after getting so close to him, his heart broke driving him into insanity. Now think of it this way, the reason why Brambleclaw didnt kill Firestar was kind of because of his love for Squirrelflight. What if Squirrelflight had chosen Ashfur? It was a 60-65% chance that Brambleclaw would've killed Firestar in the foxtrap because Squirrelflight rejected him. When the truth came out, Brambleclaw broke up with Squirrelflight because he had lost all trust in the world, Ashfur wasen't deputy and he didnt have a life of lies, so he would've most likely have been told by Squirrelflight and would've stayed with her if he hadn't known. Now speaking of the secret, the reason why Hollyleaf killed him was so he wouldnt reveal the secret. That was pretty stupid, but that was no reason why he should go to the Dark Forest. Anyways, Ashfur was a loyal warrior of ThunderClan so he deserved to go to StarClan. Now, he does have a lot in common with Mapleshade and Thistleclaw. However, Mapleshade killed cats earning her place in the Dark Forest and Thistleclaw trained in the Dark Forest to kill knowing that it was wrong, earning his place in the Dark Forest. Ashfur never trained nor killed any cats so that's why he cant really go there. Now "loving too much" is not a good excuse to be in StarClan, Mapleshade loved her kits too much. So I think that Yellowfang should've said that he regretted everything he had done as he was dying which is a more logical reason why he is in StarClan. Ashfur afterall is a pretty good and well developed character who was in my opinion was made insane because of 2 reasons:
1. Since the Erins couldnt think of a power for Hollyleaf, they had to get rid of her and what's a better way than making her go insane and kill a cat off and feed her own mother deathberries and make her run away into the tunnels to have something to regret about.
2.The fire scene was made so Squirrelflight could reveal the secret, but i think a better way to reveal the secret was that Squirrelflight wanted the three to know the truth before they died so she reveals it and Ashfur instead saves them from the fire, putting his life at risk to save the she he loved the most.
So that's why Ashfur deserved StarClan.