With your JUNO 106 and Nordlead, I dont think you need another synth
The EZ-BUS? well interestingly this model name does not come up often in conversations... The "concept" of a sound card with built-in control surface is great and very popular, but other brands and models have come out and became the new standards for this.
THOUGH I would be very careful with the whole "ohhh just sell allllll your gear! all you need is a controller and a laptop nowaday" .... I think it is FAR fetched to say this.
Where this new kind of setups DOES work fine, I really don't think it is clearly superior.
Especially if you *Already* have a hardware setup that works... COmbining all your tasks to run on 1 computer CPU will lead to some difference in what you are used to (immediacity of use, standalone operation of each component/instrument, stability, zero-latency, minimal updating/maintaining).
That's just my 2 cents, having gone back and forth between these types of setups over the last 10 years or so.