How to identify my weakest link?

First my compliments, sounds well thought out system w some astute tweaks and choices. I get that you have an itch to scratch. Where are you trying to go ? Rather than recommending a blizzard of tweaks, how is your room ( treatments ) How is your record cleaning machine ? Enjoy the music and the journey !

jim

I am a robot running a humble inquiry subroutine 

you will get more out of your table and system via vibration management putting a set of critical mass centerstage footers under the table and integrated will give you a stunning improvement.

you should maximize the core components first.

then you can decide if you want to upgrade the amp

replacing the cart is the last step.

Dave and troyAudio intellect nj

critical mass dealers

Great system!

This is one of those rare threads where most posters agree!

First check out speaker positioning and similar inepxensive tweaks as per Millercarbon, audiotroy etc, above. I also agree that changing the Kimber for something more transparent would help.

Then, of course, you need to look into upgrading the amp, as many have suggested.

Thanks for the responses.

@millercarbon 

I forgot to mention that I do have Nobsound springs under my speakers and have built a pretty nice isolation platform for the TT with recessed Nobsound springs sandwiched between some butcher block. Wrapped the butcher with wood veneer then stained and finished to match the TT. Looks pretty legit 🙂. You mention a purple fuse for the Herron and I assume some sort of vibration tape? Where can I get both of those? Thanks! 
 

I should also add that I would absolutely benefit from some room treatment but to be honest, aesthetics matter more to me. I’m just not interested in hanging clouds or placing random panels on the walls. My goal is to make the stereo sound as good as it can without making my living space look like an audio room. 
 

I like the idea of thinking of the amp and speakers as a package deal. The B&Ws are nice but can absolutely sound a bit bright depending on the recording. I feel like I’ve tamed them a bit with the tube power. Maybe different speaker cables would help even more? Copper vs. silver? The Kimbers are silver. Any more “liquid” sounding cable suggestions? 

You don't really have any weak links.  You can change a few things here and there, but to really "upgrade" you would have to make wholesale changes (sources, loudspeakers and amps).  Your thought of changing to a different cartridge is a nice idea as is the suggestion to look at acoustical room treatments.  I'd keep the Kimbers until you reach the point where you want to make major system changes.  Finally, you could always spend the money on more music purchases!