You could get a Fender Standard for that budget, or my local guitar shop has a Fender Player II Fender Player II Stratocaster, Rosewood Fingerboard, Polar White – Matchetts Music
Have you ever thought of taking the Fusion to a guitar tech to set up? Maybe they can get the neck closer to the way you want it. I'm surprised that the AS53 doesn't stay in tune. I have an AS73 and it stays in tune pretty well - just the occasional slight tweak needed. I would imagine it has the same hardware as the AS53.
Not what you think...yikes!!
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Sounds like a real bargain. I had a quick look on Reverb and other Cox Classix electric guitars are selling from about £150 second hand. Obviously, they aren't covered in stickers with repainted headstocks, but your is now in the same condition after a little work. Well done.
You can get a pretty good Ibanez new for that sort of money, so you should be able to get one of their higher spec models for the same price, second hand. hard to go wrong with a Yamaha too.