Making more restrictions and rules will make the game less playable. In my opinion, the best way to resolve such issue - if they really is a need of it - is to make even more core gates (e.g. 10-15), while every faction could have one protected by the faction's NPCs and others gates could have randomly encountered NPCs.
I do rather enjoy the limited gates (besides the issue being discussed here), would take away from the Importance of each gate, ideas of supply lines and the general enjoyment of sharing a route with all your fellow Faction members if there where more gates.
Would rather them just add more internal core zones which are rather lacking in number then more gate zones.
I really think it's acutally good feature that enemy can come to gate, I dont see what's wrong with it. It's cool pvp feature and adds to atmosphere. There are 3 entrances per gate, plus you can preview, and just enter from another gate if yours is camped.
If you could only enter from your gangs gate, it would be worse - think about it - enemy would run through core and camp your gate, and you'd be forced to enter your gate only and therefore be forced to face the campers instead of having the option of entering elsehwere.
What do you mean by preview?
I don't mind the atmosphere of having enemies at the gates but its too easy to abuse the exit zone to avoid all trouble or overwhelm those coming in.
At the very least, one gate would make more people likely to want to defend the damn thing or at least get involved in the fighting rather then just switching gate and ignoring faction issues.