If they want to reduce the suicide bombings they need to do something about respawn time after it.
The sole reason it is so attractive is that it is faster to bomb crash respawn then to try to actually fly the plane.
The proposal to move the plane spawn further out and put the rearm closer seems like a good solution to attempt, if the plane is further out it takes longer to get to the bomb point, and if the rearm is closer then the spawn, then the rearm will be faster then die and respawn as a plane again later.
Another solution would be to punish planes that die of suicide, for instance a few minute respawn timer on taking another plane.
People still suicided plenty before, they only reason it was somewhat less common perhaps was because you could get abusrd amount of kills with a bomber, and if you died someone else on your team might take the slot.