Nerfing the Orbital Command max energy to 100 down from 200 is the turtle playstyle nerf that we need
I think the easiest and best way to nerf the camping playstyle of terran is simply to lower the max energy on orbital commands.
Everyone is focusing on the strength of individual units and while that is important to consider, the real strength of terran in late game is almost entirely due to the fact that they can drop their worker count significantly while maintaining the same mining output (if not more) than the opponent.
Basically as soon as pro terrans feel like the game is going to drag out longer, they start spamming orbital commands while turtling, and when they reach about 7 orbitals, they can start progressively shedding SCVs in favor of more army (i.e. more entrenchment), without loss of total mining output. Then, once they reach about 160 army supply, it's impossible for the opponent to trade even remotely decently and they start to suffocate.
Nerfing the orbital command is the obvious choice to prevent this camping spiral. The nerf might be either in the MULE cost (but it would impact the early game too much), in the energy regeneration of the orbital command (but this would also nerf other CC abilities, which are fine), or the maximum energy amount.
In my opinion nerfing the maximum energy amount is the best approach, because it only really affects the super late game, when the terran lands a CC on a new mineral line and drops 10 MULEs to skyrocket their income to 4000+, while having 40 SCVs. And the opponent has no way to deny it since terran has 160 army supply of ghost / tank to defend it.