The other problem is I already have a Les Paul Traditional so it doesn't do anything new over it
I would say that the 594 offers more than a LP Traditional - for a start it has Coil Splitting and, if you bought an 'older' model, locking tuners. They are better made in general and more stable too - but I know you can find some Gibson's with no/minimal fit and finish issues that hold tune well.
The Custom 24 is a bit hotter in the Pups but its also a different instrument. Its certainly more modern as well as being thinner in the body, longer scale length, different neck (comes in Pattern Thin and Pattern Regular so you may want to check which, if any, you prefer) and trem - although they have done stop tail versions in the past. The sound will also be different - even if you had the same Pups as the neck Pick up is closer to the bridge on the Cu24 - not as much separation between the two Pups.
I own both a Cu24 and 594 (as well as a couple of other PRS's) and like them both because they are 'different'. If you want a 'hot' PRS, then maybe look at the Tremonti or Cu24 Floyd - both have hot bridge Pups around 15k. The 85/15's maybe hotter than a 594 but they are not what I call 'hot'. Anything under 10k (bridge) is not hot in my opinion and that suits me fine as I prefer lower output. If I want more, I can always use a boost or use a very high gain amp (or amp model if you use a modeller).
At the end of the day though, the choice will have to be your own and no-one can really tell you what you should do, what you should like and prefer. Just because I prefer lower output Pups doesn't mean that you should too and stick with the 594, tell you that you should trade in for a Custom 24 or change the Pups in your 594. Its you that will have to play the guitar, you that will have to make it work for you, you that will have to live with the decision...
I would suggest though that you try making a new patch on your Axe FX with a high gain amp model and maybe adding a boost in front. Experiment with what you have already rather than jump in to a trade when you may not need to. Whatever PRS you end up with, it won't be a 'bad' choice at all as they are superb quality instruments. You already have a CE24 anyway which is generally a bit brighter and snappier than a regular Core due to the slightly different bridge and bolt on maple neck. Only you will know if its worth considering a Core Custom 24 to go with the CE24 instead of the 594 or whether its better to look at experimenting with Axe FX, buying a boost pedal or even swapping Pups (if you do, keep the 58/15 LT's...) but the only advice I feel I can give is to fully explore your gear first as I know the 594 can do high gain well with great clarity too with the stock Pups but whether that's 'exactly' what you are looking for or not, you will have to experiment with yourself....