Right now having an emperor on a low population servers is an incredible advantage. One emperor can often equal the entire population opposing him or her on those servers, making it impossible to dethrone them if they got followers.
On high population servers emperors are a danger and a problem but it can be countered, not so on low population servers.
I suggest that the bonuses an emperor gains is scaled to the population of the enemy side that face them. For example at 1 bar its only +25% to the stats, 2 bars +50%, 3 bars +75% and only at locked does the emperor gain the +100%.
That would do wonders to break the stalemate and "buff server" problem on the low population servers.