In what areas will being on a PvP server make a difference?
In Star Wars: The Old Republic, while characters from both sides will visit the same planets, they generally do so at different level brackets and visit different areas in those worlds. For example, playing on a PvE server I haven't come across any players of the other faction just doing my world quests -- only if I go out of my way to explore planets will I occasionally catch a glimpse an 'enemy' player.
I'm curious if this is a result of "phasing", and so such things don't happen on PvP servers, or if it is just how the wolrds are designed... and if the latter, then how much difference does being on a PvP server actually make?
Solution 1:
It it not a result of phasing, phasing only affects the storyline elements of play and are generally localized to certain buildings, caves, etc. They will not apply to large parts of planets.
It's a little bit to do with a low server population across all servers at the moment, so a lot of people won't be crossing your path given how large the planets are.
So to answer your question, the only differences that you see will be the automatic flagging of PVP of other people in "common" areas. You will have no control over this and open world PVP will become part of the leveling process should you run across opposing faction players.
Solution 2:
It is how the worlds are designed.
The start areas are usually on opposite sides of the world maps. As you progress in the missions you tend to get closer together. On planets that have the bonus missions you will be in the same areas and will run into each other quite often.
The planet Voss seems to send both factions to the same mission areas right away. The Shrine of Healing area gets a lot of people killed.
The level 50 daily mission areas on Ilum and Section X have missions where Imperial and Republic players will be in the same areas. This can result in a lot of conflict.