I'm a returning player from a 3 year+ hiatus thanks to cross play and while I've fully caught up on quests and syndicates etc. I found myself needing a lot of cryotic for Fortuna and other things and it seems doing excavation is every bit as boring and dull as it used to be for many reasons:
Enemy spawns are a coin toss. Sometimes there's nobody around for entire excavators while other times there's just barley enough to distract you from the ticking timer taking to long.
Ever reliance on enemies carry power cores which ties to the enemy spawning rates. A lot of the times outside of Duviri there just isn't enough power core carriers
The mission type just isn't very engaging
There's probably more I can't think of right now but it feels slow unrewarding when I play.
General Improvements
Fix the First two things on the previous list.
Rework
Hardest part and one that's more than likely not gonna happen.
Make the Excavator simply just a timer with no required filling of power cores (probably the least likely thing here because it requires changing challenges from the Nightwave)
Change Power cores and the mechanic around them - (Instead of filling the charge make power cores actually speed up the process reducing the time required for a dig if only slightly per core, a potential tweak or addition could come in allowing players who hold the power core and kill other core carriers acts as a overcharge to the core increasing its effectiveness and decreasing the time per dig even more. The new nightwave challenge could be "Finish a dig in X amount of time")
Obviously the spawn rates of the core carriers and enemies would also have to increase slightly at lower levels and potentially increase its health and shields
I like a lot of the new mission types I have returned to, so many slight variations to older modes that keep the player more engaged instead of just standing around waiting for enemies to come to you and I simply enjoy just throwing ideas out there and seeing what happens.