mike Both scenarios you are mentioning are happening, Agencies are given the option to choose which Geo location group their website will be hosted to, also in case a serer gets overloaded high usage websites are moved to a server less load to make sure everything runs smoothly .
mike lets say you have a plan 20 websites for 20$ (u can relate to this plan right) (assuming 1cpu/1gb or x amount) u know that you are giving the reseller 20cpu and 20GB ram ? now lets say u have 5 only resellers of these.... 5 x 20cpu=100cpu and they are actually using only 15% u need 16 core cpu minimum which costs around ± 60$ . now you have licenses + other costs on top.
This is exactly why i am saying you need limits per website and also per package, so you can configure the pool of resources all websites can use maximun, and the resources a website can use individually, as an example package can have 5 core and each website can use up to 1, how this will be fine tuned - fitted for general use is up to enhance to decide, but the current system doesn't really work.
I want also to repeat, that we don't currently use enhance for production as web hosting Panel,is used only with a few selected clients, as a Pilot program., if in the end Enhance doesn't meet our needs, we will result into building an in house solution similar to enhance, but for now it looks promising