I've got to chime in as I've got two old original RG550s
IMHO Ibanez don't make guitars as good as they did in the later half of the '80s up to about '94/5
About 1999 I went out to buy an RG550, they were all horrible, not a patch on my mates early RG550. Rg550s can be dull if they don't have a maple fingerboard, you can't buy one now and the stock pickups aren't as good now as they were back then. RG550s are bright sounding guitars, and should feel responsive, resonant and dynamic, with the maple board they're the perfect 80s rock axe - they scream. I did have a RG565 with a rosewood board - not as good a tone as the maple boards.
Here's part of the theory - 1990 an RG550 was about £500, about the price of a good top line US Strat plus. I don't buy into any excuse about modern manufacturing lowering the cost, they're built cheaper and feel cheaper.
Prestige models are a little better, but not a patch on the old custom shop axes. The JS and JEM range feel like toys, they used to feel, well, expensive, like a US Jackson or top line ESP. Oh and I prefer the original Edge trem and Lo Pro edge over the newer trems.
Try an old one, I'll drag mine to Music Live, try that, everybody who does offers to buy it, and I got it for £50 in bits! Proof enough for me that they don't make 'em like they used to.