Been a long while since I commented on anything MRP but this is a topic that's come up so frequently I feel my below comments could aid in any decision to be made.
This was a policy for a long while, however it was inconsistently enforced and Staff weren't willing to not play war just to ensure people don't basecamp. Sometimes they did, sometimes it'd just be a respawn, but the toxicity/oneupmanship on the server meant this was inconsistent and drama always followed.
This might make it harder for the less-skilled players to basecamp, but it's not likely to have a great effect and has negative repercussions on sniper use generally, unrelated to basecamping
Would be interesting to try, but the issue with this sort of approach has always been distance/routes between bases and objectives, and where it's considered reasonable. You would need this zone to cover everywhere that rendered the base, whilst not making it encroach on what would be reasonable positions to defend objectives. Could be decided on, but it's one of those things that will also massively change depending on the map.
Basecamping does need a solution, as it's one of the big killers of new player population.
When I was Manager, and attempted to counter some of the basecamping issues (you will never solve all of them), I checked a few other servers for their basecamping rules. The most I could find that represented a basecamping rule on other servers was one along the lines of "only engage where the firefight is" or words to that effect, meaning only fight where there is the main fighting. A soft version of this was trialed on the server for a couple of weeks, and enforcement by faction leaders was hit and miss depending on the faction, leader, previous war.
Another method tried when I was Manager was to set up 'zones' that went outside of the respective bases, and basecamping would be decided depending on if you killed an enemy whilst they were in their zone. This had a lot of objections from the traditional basecampers, and really again depends on the map in-use at the time, however did generally succeed in allowing players to get closer 'to the fight' than previous render rules.
In my mind, basecamping rules should focus on where the 'defenders' are, rather than where the 'basecampers' are.
The key thing is going to be, whatever is decided, it is going to have to be enforced. If it's decided as a faction issue, and faction leaders aren't pressing on it, then the Staff/Admin/Management team would have to crack down on factions. If it's decided a staff thing, Staff/Admin/Management will have to crack down on enforcement for everyone, which will mean some staff not playing all of a war if basecamping becomes an issue in a war.