1.) Not really, the game can do anything it wants. They could allow you to execute every action at once, within a single second. You could, as some bosses can, cast multiple spells at once. Server or client limitiation has little impact here.
2.) Yes indeed, it's important for the healer to raise from a safe spot and the dps to time it. Certain fights are more difficult to do this in than others, but it's all about coordination, and common sense. Things can happen like the freshly raised target being the victim of land slide, but these things happen.
I have an understanding of game programming and client/server communications. I'm no professional so I keep my critques to a minimum, but take care not to give them a lot of leeway on bad design choices.
Things like not being able to stack macros are a sort of an additional straw to break the camel's back, there's not so bad in themselves, but are frustrating.