Game Development (Environment) theory and discussion:
I am presently making a game, RTS like the name suggests that allows the player to primarily use traps that he builds to trap the enemy (you can also attack the enemy with your NPC's you create but they are limited in this to encourage the traps capabilities) I planned to do this (since they are traps being used) within a base so that the traps can be used at a few select chokepoints to slow and even push back the progress of the enemy.

Upon looking for other RTS's to see common layout for a similar type game I found no games of today (that have the Age of Empires type building units and buildings type of gameplay) within a closed off base environment. All RTS's of today are in the open world so that more menueverability can be achieved by the player and the developer and also the variety of gameplay cannot be limited.

Is putting a RTS in a environment such as a large base such a bad idea?
Should I transition to have the base in one area where it can be entered in by the environment where the origional enemy comes from (from perhaps his base on the other side of a valley or such)?

This way the player and enemy can express themselves more in tactics rather than they would in closed environment. In short what do you think? Where should I place my game levels and what are the downside/upsides to either way of going about it?