Deep Blue wrote:That map really favors turtle strategies but can't be helped i guess...
It most definitely can be helped.
Best way to discourage "turtling" in video games is to have multiple objectives spread throughout the map (turtling is ineffective in multiplayer RTS, for example, because turtling gives your opponent easy access to the entire map's resources).
A trivial solution (not necessarily a good one, but bear with me here) would be for simple "powerups" that significantly boost damage or stats to appear in the middle of the map around turn 6-7 if the area is uncontested.
Another trivial "stalemate-breaker" solution would be to implement a second victory option involving bringing your Notable to the center and holding it for a set time (much like King of the Hill).