There is a big difference between paralleling batteries for "more current" or "more run time".

200 amps at 12 volt will support about 2,000 watt. If 2,000 watts is all you need for peak power, then a 12 volt bank will work. Each 100 amp hour battery can give you that 2,000 watts for just 30 minutes. If you need 2,000 watts all day, 24 hours, then you need 48 Kilowatt Hours of battery. That would be 4,000 amp hours. There is no problem with paralleling batteries to get a long run time, but if you need more current than a single battery can support, then you need to be very careful to ensure the batteries are sharing the current well. Equal length of identical cable from each battery to the buss bar is a good start. Each battery should be fused within it's safe limits. And the wire needs to be sized to handle more than the fuse. The main fuse after all the batteries are combined needs to be less than the buss bar rating. And the wire after the fuse must be able to handle that fuse current.

I am very conservative. My rule of thumb is to only expect 50% more current each time you double the batteries. That way you should be very safe. For example, if each battery can take 50 amps, and you parallel 2, you can expect to safely get 75 amps. Parallel 4 and you can pull 112.5 amps. Double it again to 8 and you have 168.75 amps. As I said, this is VERY conservative and you can certainly pull more current, but if you design around this, you should never have a problem with current sharing. You should still do you best to use equal lengths and feed the groups from opposite ends. Balance the current the best you can, and everything runs cool and you never have a problem. This should also be a low enough current that the separate parallel packs should be able to easily self balance between them through the charge and discharge cycles. If you are running more current, any mismatch between the banks will cause the state of charge between the banks to differ more and more. The less current you have on each bank, the better the BMS will be at balancing the cells as well.

If you do have 2 battery feeds, it does make sense to put them on each end of the buss bar and put the loads in the middle. This way the buss bar material is only taking half of the current. It is like putting 2 buss bars in parallel. I did this on my negative bar between my batteries and the BMS input. It is a 4 position bar, so the battery strings go to posts 1 and 4, and the two cables to the BMS go on posts 2 and 3.