When I take over an opponent, frequently I'd like to add a religion I have a shrine for to all my new cities (or if I took over a shrine, add that religion to all my cities). Making missionaries and sending them off is no problem until I get down to the last few. I have to click on the religion thing to see what cities are missing what religions, then find the cities and get the right guys going the right place. Not the worst job in the world, but adding 3 religions to 10 cities is tedious.

I'd like to see missionaries have an automated spread religion button. And maybe a second to spread religion to other nations.

Well with Religious Shrines (wonders) religion is suppose to spead faster and without missonaries, but I can see the problem. Sending out Missionaries takes too much time, especially if you are converting civilizations on Large or Huge maps and are limited to only 3 missionaries at a time. Automating missionaries like workers is a good idea, but then you still have to build missionaries. Maybe there is another way to improve it...

Sending out Missionaries takes too much time, especially if you are converting civilizations on Large or Huge maps and are limited to only 3 missionaries at a time.

On that note, why not increase the limit to 4 for Large maps and 5 for Huge maps. Having the limit remain at three is ridiculous for Huge maps.

no because on huge maps their are more civs so the total amount of missionaries also increases.