first thing I'd reccommend is to get small strings, I swear by Ernie Ball Super Slinkies (pink package 42-9 size range). Especially on an Ibanez, they're pretty much essential I'd say, you have such a slinky guitar anyways, built for speed, so get the fastest strings too...it also makes playing 10 times easier, but you also get so used to it, that playing other guits in the store, especially fender and gibson, they are much more demanding to get the same level of proficiency on, and they will always be a little sloppy compared to an Ibanez, so I have no use for any other kind of electric basically, just a classical is the other thing I have and love as far as guits go.

I also don't pick very hard usually, especially when I play ultra fast...I try to give it a little sharpness when I pluck the string, but it is always much softer than when I pluck it at medium and slow tempos with more "articulation" - maybe this is because I use my foreqarm for top speed, not my wrist, but anyhow, I have decent tone even at high speeds.

I have an RG550 from about a dozen years ago (bought it 10-11 years ago for discount price because the most forward pickup setting didn't work, but hey I don't care...it turned out the wiring needed to be re-soddered, that's all, but it cuts out most of the time now anyhow...gotta get that re-done).

Anyhow, it sounds to me like your strings are the plunky part of the sound. A simple 8 dollar thing like that can make all the difference in the world...