System recommendations

Looks like a well balanced system.
IMHO, the best bang for the buck for an improvement after the room treatment is to upgrade the preamp. Changing speakers will bring more change, but at higher cost.
However, you might want to have a long term plan to upgrade the whole system (which will cost at least 20K for a new system and 10K for used).
For example of a used system, I have Plinius SA102 (2K), Audible Illusions M3B (2K), Oppo 105 (1K), and Gershman Avant Garde (6K). Such system will definitely sound superior to your current system.
My 2 cents.

@stereo5 
I have never heard before that Mondial had anything to do with Mark Levinson. Mondial was a small company out of upstate New York. To my knowledge, Mondial made only Aragon and Acurus products. The 4004 amp by Aragon was considered a poor man's Krell, because supposedly Dan D'agostino had a hand in the design. 

Never the less, the 8008 was a very good amp with ample clean power. I have owned multiple Aragon amps over the years and the 8008 is likely not the weak point. The Aragon preamps were not held in as high regard as their amps. I have never owned one of their preamps, so I can't say if that is a bottle neck or not.

You question is a tough one. You have, I think, a very good system. Really difficult to find fault with it. However you are expressing a desire to improve what you have. This is a clue for me that you really want to make a substantial change. With that in mind, it's time to shop for new loudspeakers but perhaps wait to purchase until you move into your new space. You want to make a big move up, avoid making a sideways change, it will not satisfy. 

I agree with @stereo5 that the biggest improvement will be in your speakers which may be the weak spot. However, I also agree with @ghdprentice in the importance of the preamp. And this too is a weak spot. Which is the biggest bottleneck is hard to say.
You may be surprised at how much more  Rel subs can add to the speakers. They magnify not just the bass but the whole freq range This makes for much better imaging. So that may be your best option. But at some point you need to upgrade your preamp. Tubes should be considered

I would avoid lateral moves. I found, in general,  if you double the cost you get an “oh wow”. You always want to be pleasantly surprised at how much better the change has made your system

The Aragon amp you own was made by Mondial which also manufactured Mark Levinson during that time.  They are good products. I wouldn’t change the amp or pre and I wouldn’t bother trying different cables.  Speakers will make the most difference either by integrating a subwoofer into the system or changing the Dynaudio speakers. 

Thank you for the responses so far.  I do need to work on the room a bit, although I will be moving over the next 12 months.  The current room I have has the left speaker along a wall and the right is more open.  The left side sounds a bit more dynamic and precise if that makes sense. 

The Aragon 8008 has plenty of current which the Dynaudio's like, and the bass response is very good. They are about 3-4 feet from the rear wall.  I thought about the new Halo amps as a replacement for the Aragon 8008 & 28k, but that might be a lateral move unless I go up to the JC1+.   

I’m no fan of ports, if so, front only.

Those speakers ought to have darn good bass without subs. Perhaps tighten the bass by closing the rear ports.

Did you ever try Dynaudio’s Port Plugs? Or blocking/stuffing them yourself?

Dynaudio’s Speaker Positioning Info is very informative

https://www.dynaudio.com/discontinued-models/excite/x44/support/manual/en/positioning-installation

excerpt:

"Dynaudio speakers are designed to perform at their best when positioned as far from any walls as possible. Ideally, try to aim for a minimum distance of 50 cm (18 in) from each speaker to any wall. Diagram 3 illustrates room boundary distances.

Diagram 3: Distance to walls

Speaker positioning – using port plugs

If your Dynaudio speakers have reflex ports and are supplied with foam plugs, these can be fitted to reduce the bass emphasis that may be apparent if the speakers are placed close to room boundaries. Some Dynaudio port plugs can be split to provide optional levels of bass volume reduction. For mild bass reduction, fit only the outer foam ring by sliding it in the port tube so that it sits just inside the flared port exit – making sure it retains its shape to minimise airflow turbulence. For more extreme bass reduction, fit the complete plug so that the port is blocked. Diagram 4 illustrates the use of port plugs and their effect on speaker frequency response."

.....................................................

After closing the rear ports, ’tightening’ the front bass, then, discover if you want ’lower’ bass (not ’more’ bass).

IF so, I recommend a ’stereo pair’ of front facing self-powered subs located adjacent to the mains. Both the fundamentals and their overtones, i.e. 36, 72, 144 ... provide directional information, you will know where the bass player is standing!

Even if you have plenty of bass at normal listening levels:

For low level listening, due to our ear’s variable characteristics, you need to boost the bass to maintain it’s volume relative to other frequencies,

the easiest is a fletcher munson filter, progressively increased bass as volume diminishes.

https://en.wikipedia.org/wiki/Equal-loudness_contour

Proper setup, point of engagement, of ’loudness’ (stupid name) filters is important, many misuse it.

For instance KEF LS50's are world's apart from Ohm Walsh's, though each has their fans! As posted above you can stick with the Dynaudio's and just add a sub or two or three or four ... this would give a big improvement in bass power and definition! 

Keep the Aragon preamp and amp. They were expensive when new and were considered top category components! The biggest improvement will be new speakers! The Dynaudio Excite's are excellent! What don't you like about them? I am surprised that millercarbon hasn't already recommended Tekton's! Speakers are such a personal matter that it is difficult to make a recommendation without knowing what your musical choices are! Maybe you could elaborate!

I’ve never heard Aragon so can’t comment on that but agree with millcarbon that speaker & component isolation improves sound quality a lot.
In addition to that:
- A couple of subs (more than one at least) would be a great improvement.
- Although you didn’t mention your room, if you haven’t done anything with the first reflection points, you would be amazed at the improvements there.

What kind of sonics are you trying to improve upon with your speakers?  I recall those Dynaudio's leaning to the treble side.

I would start with the preamp. There is a whole world of fantastic preamps out there. This is always the center of my system around which I change components. If you do not have a huge budget, I would recommend used high-end. The value is there for years to decades. Think Tubed preamps like those from Conrad Johnson, Audio Research, VAC. Very good solid state are also available from Pass and others, but I have found you tend to get a more natural sound for less money with tubed equipment.

OMG and people think I have a big head for invoking Einstein!

Of course you can get more out of your speakers. A lot more. Put them on Townshend Podiums. Put all your other stuff on Pods. I would do this first, unless you have some major problem with one of your other components, which I assume you do not as otherwise would have said so. Podiums will be more than getting more from your speakers, they will be a major speaker/system/room upgrade. Read the comments from those of us who have done so, you will see.