I love it. I almost always play Fin/Pro this days.
I play custom games / deity - no tech trading / advanced start ( to start with 2-3 city, no bonus tech) and most importantly aggressive AI and raging barbs.
Not long ago was backstabbed by Zara Yacob with 164 units. 20 catapult, about 30-30-30-30 spear, axe, sword, chariot, some horseman and a very few modern unit. (longbows i think)
I managed to pull 12 longbow, 3 of them heroes with drill 4 / city def 3 and the heroes had hill defense 2 and one of them 2 combat.
I won the siege with no losses.
The tactic it requires to play protective my style is -
1. go cottage eco.
2. create border cities on hills, if i can later i build fortresses on forested hills.
3. get exp on barbs and provoke wars earliest possible with as many civ as you can but not all and do not attack so after peace the modifiers are not horrible.
4. get a few archer hero early they can be godlike very soon, and they will be helped by elite defenders in case you are unlucky.
If the score leader waging war against you it hurt his economy and more importantly he does not build helpful city improvements. It hurts you only a little (pillaged border city fields)
It seems that in deity it is actually better if a strong enemy attack me, than if it attacks a weak one. I can defend easily - but he will conquer some cities from the AI.