I found a way to improve BvC stomping abilities with game mechanics. Bad news is it requires me to remove Highlord's from the build unless I go without OaK which is inferior option.
What is ActionFlag?
ActionFlag is a frame at which character actually casts a spell. Let's check sorceress in a table below
At 105 FCR she casts a spell every 8 frames. However, of those 8 frames, the spell is actually cast at fifth frame and last 3 frames count towards backswing animation. This means if sorceress wants to escape from a trap lock, she will manage to do that at frame 5 of casting.
If we check for 200 FCR, we know she casts spells at 7 frames, but the actual spell is cast at frame 4 which gives her 1 frame less to cast teleport compared to 105 FCR. This is why 200 FCR sorc is much harder to lock, not just because she moves so quickly around the map.
Barbarian FCR considerations - 37 and 63 FCR
Those two are what matters for a barb with 37 being the most common one to hit via Arachnid Mesh and Trang gloves. Now, there is a thing to consider here, let's check the table.
At 37 FCR barb casts spells every 10 frames while the actual spell is cast at frame 8, backswing is 2 frames.
At 39 FCR barb casts spells every 10 frames, but the actual spell is cast at frame 7, backswing is 3 frames. Why is that important?
Let's consider telestomping + whirlwind. Whirlwind hits at frame 4.
At 37 FCR, upon teleporting on his target, barbarian will do 2 frames of backswing following with whirlwind meaning he should hit his target at frame 6.
At 39 FCR barbarian will tele, then do 3 frames backswing and then do whirlwind leading him to hit at frame 7. That is 1 frame slower hit!
This means, if barb wants to have more success hitting his target upon telestomp, he should pack 37 or 38 FCR exactly, going with 39 and more gives him less chance to hit his target upon stomping. This could be achieved with Trang gloves and 17-18 FCR amulet, or 7-8 FCR belt and fcr ring while maintaining Highlord's for extra damage.
Is this worthy tradeoff, losing extra damage from Highlord's for that extra frame we gain? Against spellcasters, possibly yes. Highlord's adds a little bit of damage, but that 1 faster frame hitting might give barb much more damage if he actually hits his opponents. Note, at 63 FCR situation is the same as with 37 FCR with exception spells are cast 1 frame faster.
Imagine how much 1 frame of casting is felt, I'd assume same might apply to a whirlwind stomping. This needs to be tested of course. And we have to remember Berserk skill is here as well, although only as addition, not a main skill.
Other builds consideration
Javazon wants 68 FCR to have only 3 frames backswing, anything below leads to slower stomping abilities while Charged Strike is her strongest skill by far.
With melee paladin, at 75 FCR his backswing is 1 frame less than at 86 FCR, but I don't think someone can overstack FCR on him. Anything else is straightforward as common knowledge is