Would reducing TTC really help disperse zergs in Cyrodil or would it be a bandaid solution that zergs would learn to circumvent?
I know this is hard for folks when they first get into PVP but it is really designed for coordinated group play. It is difficult to accomplish much solo. If you want to have a better time in Cyr find a PVP guild and run with them.
As for your question. No, reducing time to cap would not change much if anything. A decent small group easily flags and takes a keep before a zerg can arrive to defend it currently.
My experience on PCNA is the best way to break up the red or blue mega faction stacks (60+ groups) that commonly exist is to cap chain cap quickly behind enemy lines making sure to take keeps that obscure the current line between blue and red. This actually gets them fighting about 50% of the time and often confuses the pugs as to where the real action is. Hats off to the purples on their general ability to herd their pugs though. 9/10 times they keep them in one big mega zerg focused on yellow and somewhere at least remotely useful. I can never even find yellow's pugs. They seem to either be picking flowers or chasing around the two guys running cheat engine at a resource deep in yellow territory to farm them (there is always at least one 2 guys doing this deep in yellow's territory and often several).
In the end I don't really think there is a solution to the whole zerg thing beyond people getting in guilds and running in organized groups. Perhaps if guilds had que priority in Cyr that would essentially keep pugs out and you would only have autonomous independently thinking groups instead of whatever hive mind a zerg generates. You could also turn off zone chat to prevent herding of the pugs but that also hinders them forming groups and makes their short miserable lives even more miserable. Though these things would lessen the giant zerg balls I don't think they are probably the best idea. Zergs are just going to be a thing. At least now they don't have AOE cap to make them difficult to destroy.
It would promote zerging even more.
The way to reduce zerging is:
Nerf Earthgore, nerf Xv1 tools, change distance deto, increase the player cap of Cyrodiil , decentralise the map and nerf gankers
Why does this help?
Earthgore has a high cooldown but when used it gives everyone in its radius invincibility. With more people using it in a group the longer this invincibility period is thus people stack more as they can't die.
Xv1 Tools promote zerging as bad players who have no chance against good players see how they can easily kill them with things like: poisons, shieldbreaker, procs, defile stacking, siphoner cp
If you nerf it people have to learn to play to pvp so zergs are more vulnerable to smaller groups
Distance deto was ment to be a tool to counter zergs but it only made zergs more powerful as it creates an AoE area around the group where all people entering it when they go off die on the flip side one trying to bomb the zerg will miserably fail.
Change it to work similar to inevitable detonation but reduce the channel to 1 sec for both morphs.
Then change distance deto to explode immediately if 10 enemies are in its range. Making it useless for zergs and good for solo or small groups who try to fight zergs
The player cap of Cyrodiil is one reason we have as much lag and zerging as we have right now.
The cap is around 150 people per alliance. These often stack on one or 2 keeps while the rest of the keeps are empty, however it's hard to take keeps as the zergs can always switch between the 1 or 2 keeps which are attacked at the same time as many people are too scared to attack a keep with 7-10 people
By increasing the cap there are more people to attack keeps and to defend them, making it possible to attack multiple keeps at the time thus decentralising fights from 80v80 or 120v120v120 on one keep to 40v40v40 on several keeps which reduces lags.
The map is completely centralised around the 6 emp keeps which are often crowded around 3 choke points at Alessia Bridge, Chalman gate and Ash gate.
There aren't literally no incentives to defend or take keeps like Dragon, Brindle or Drake also there are huge parts of the map which are absolutely dead and no one ever goes there even the 3 towns are often ignored as they don't affect the map or the campaign results
There need to be incentives to go to other parts of the map for players of different group sizes.
This will help to prevent megazergs as they can't defend everything if they don't split up.
The last point is to nerf gankers, before gankers got buffed by new sets, procs, poisons, sneak stun etc, more people went to play solo but with the numbers of gankers rising the more "bad players" started to zerg as they simply got one shotted everytime they went somewhere and with a big group gankers are no problem as they will simply be zerged
Zergs have always been in Cyrodiil and really are not more prevalent today than before. Reducing the time to take a keep merely encourage larger zerg to defend it and that keeps will flip more often.
As for the suggestion you mentioned for getting weapons, that is merely an attempt at a justification for getting the weapons via Cyrodiil activity. Nothing more.
You can already break a door in less than 30 secs. Taking an undefended keep from start to finish is a process that takes no more than 2 mins... you really want to reduce it even more?
That would not give any chance to defend it, when someone is inside and calls for help... as it is now, you can barely make it from the adjacent keep before they are already inside the inner... specially if they are organized.