Moving coil with a bit less leading edge

You will certainly get a more rounded, less edgy sound with a non-stone Koetsu (i.e., not the jades, or coralstone, etc). But, that comes with some woolly quality and overly prominent (and slow) upper bass.

I like Allaert cartridges for a smoother and refined sound while not giving up too much in dynamics.

Syntax raised a good point about cartridge arm compatibility. The Lyra cartridges have metal bodies designed to convey vibrational energy from the cartridge body into the arm for the arm to dampen/dissipate. The arm must be well designed for that task to get the most out of those cartridges. In some threads, Jonathan Carr, the designer of Lyra cartridges mentions some arms he considered well up to the task (sorry I cannot remember which arms are mentioned).

Opus88,

Your comments about wanting a little less edge to the initial transient attack and more natural decay to the notes is really better addressed by the kind of phonostage (as well as the rest of the amplification train). That describes the tube sound vs. solid state more than one cartridge vs. another cartridge.

Opus88,

Do you use other sources (CD, SACD, etc), and if so, how do they sound playing classical music? Knowing how the rest of the system sounds would at least help to determine if your issues are isolated to the analogue part of your system.

If the issue IS in the choice of analogue gear, and not a adjustment issue, I think you need to focus on the combination of cartridge and phonostage. A "wrong" combination would be most obviously manifest in handling of upper frequencies. I find that with any given cartridge, a wide range of results can be had with different phonostages and it is not easy to "predict" the outcome based on the reputation of the products.

Thus, at best, I can only offer a rough guess that something like the lower price range Koetsu cartridges might work. Perhaps some non-MC cartridges should also be considered, such as Grado cartridges (somewhat blunted transients).

If you stick with MC cartridges, you might want to look into alternative MC step up transformers (SUT) and to bypass the SUT in the EAR phonostage. I am not personally familiar with your EAR phonostage, but, others have reported that the built in SUT is not as stellar as the active stages. The "wrong" SUT can sound excessively edgy and sibilant. There are MANY different separate SUT on the market and perhaps one would work better than the built-in unit. It is also easier to arrange to audition transformers than it is to audition cartridges.