All electronic drum kits even today basically just play back recorded samples with triggers shaped to match traditional drums. No matter how good the samples themselves are, the idea that each hit triggers a specific sample will never sound realistic when the same instrument (especially cymbals) is struck several times while it's still ringing.
This is because drum heads and cymbals don't behave linearly. The same cymbal hit in the same spot twice as hard doesn't sound just twice as loud. Instead, a larger proportion of the energy will be in higher frequencies, corresponding to denser modes of vibrations, and the sound pressure will be less than twice as much.
The same is true for two hits of the same cymbal at different times. When you hit a cymbal that's already ringing, the added energy will quickly shift to higher frequencies than it would in a previously still one.
In order to simulate this effect in electronic drums, the sound module would have to either use a non-sample-based model to create sound, or perhaps select a different sample based on the frequency content of the currently playing mix of the same instrument. It will be interesting to see who gets there first. Yamaha, Roland, Korg, or maybe some newcomer?
Electro-acoustic cymbals on the other hand are actual physical cymbals, whose sound is picked up, amplified, and perhaps equalized electr(on)ically, so they should in theory behave like traditional ones.