Hi,
 
I find guitar tone "simulators" often lacking in the punch & dynamics aspects compared with a real amp.  Was wanting to get some opinion on preferred methods and plugs for adding punch & dynamics to distorted guitars.  Something that could be crafted to allow the leading edge of attack through, or else expand it.  (And be mixed back in with the original signal I suspect). 
 
 
Sonic

It's the distortion process itself that kills dynamics. Kind of its thing. 
 
Once heavy distortion has been applied, there simply are no transients left to emphasize or recover. The reason you don't notice that as much with analog amplifiers is that a) they don't necessarily distort immediately and b) the amount of distortion is proportionate to the input signal. Some amp sims try to emulate that, to varying degrees of success. I'd focus on trying out different amp sims rather than attempting to mitigate loss of dynamics with processing.
 
That said, parallel compression can be used to good effect. Mix in a clean signal with a high compression ratio and long attack and release times.

It is that exact issue that keeps me using an amp and a mike for guitar. You loose that attach the minute anything digital is involved. My Blackstar is the closest I have come to a Tube amp "feel" with a modeling system. But the minute I plug back into my old Fender Princeton I notice the difference in response.  
Pedal boards always did that too, they just felt sluggish. 
I'd love to try one of those high end systems like https://www.fractalaudio.com/ax8-amp-modeler-multi-effects/
 

I need something that will latch onto the attack transients so I can accentuate them.  I set my gain amp profiles in a way that still allows for some dynamics to sneak through - a balance between having just enough gain to remain playable while recording.  So I usually have a bit of dynamics, just enough that I was hoping some plug might be able latch onto the attack transients so I could accentuate them (overly so if necessary and then re-combine in parallel processing fashion).
 
Already tried a few compressors without much luck....
 
Sonic
 
 

You could see if a transient designer would work, by which I mean grab that initial attack and emphasise it. 

give sknote grasso a look

Compressors are the opposite of what’s needed to boost transients compared to the average signal level.

A transient shaping plugin after the sim might help.

Lack of transients in guitar setups is often due to using too much gain/distortion which compresses the signal too much. The problem I’ve found with sims is that they simply don’t respond (or sound) like valves do, or like transistor fuzzes, distortion pedals etc. do either.

My “silent recording guitar” setup is an amp (currently an Orange Rocker 15 Terror head) into a Palmer speaker emulating DI and load box and a few good pedals. Sounds and feels very convincing. As does the same amp on it’s lowest power setting which is around 0.25-0.5 Watts. Some of the small sub-1Watt amps are worth considering as well, e.g. the Blackheart one. The Blackstar one is popular as well, but much too noisy for my tastes.

The Sansamp Character series and Flyrigs are also worth taking a look at. For a bunch of solid state circuits they do a good job.

I'm using a Kemper at the moment. It has great speaker/IR emulation, however I find the amp emulation is a bit compressed compared to a real amp, so the end result sort of cancels each other out. 

No plugin for me ,
but a self builded sound iso­la­tion cabinet and some recordings in a rehearsel room
fit my needs..
And:
less gain-/ distortion  and more master volume.

A lot of guitarists overdo the distortion. I find that my tone is much improved if I back off the gain until it just starts to clean up.