Regeneration Master: Regen is important with Johanna. Even though her trait allows her to take abuse you will also be tanking merc camps with lane partner and this helps a lot. If the team is heavy with auto attacks though then go with Reinforce.

Laws of Hope: Boosts your regen and any heals when your support isn't around or don't have one. Can get up to 50 per second which is pretty good without amplified healing being picked. Gives you a nice mini first aid to cast also.

The Crusade Marches On: Iron skin is super important and cheap on mana. You are immune to CC (including tower slows and boss AOE) and get a significant shield that allows you to regen a lot of life since you're not taking damage. Most people like Battle Momentum but you don't want to get into the habit of casting too much and always being low on mana. Your trait is what makes Johanna so amazing anyways.

Falling Sword: Either of these talents are good, but I like this one in case I need to escape or jump some squishies in the back line. Your opponents can't see where you will land and you're not visible on the minimap. It's great for surprise initiation of a teamfight from bushes or fog of war. Never see it coming. It's Pop up still breaks channeled abilities like a stun would. Also shield is a skill-shot so you can potentially miss with it.

Burning Rage: Great for damage since you're always in the middle of the action. Also helps with merc camps. Why not get free damage in that costs zero mana.

Subdue is also good if you find yourself with a good ganking team comp.

I don't like Hold Your Ground because let's face it. If the enemy team see's you with your trait up they are just going to ignore you. It usually never triggers and is a waste from my experience.

Imposing Presence:
This is a great skill and I'm glad all the warriors got it. Counters a lot of auto attack heavy heroes and grants a significant boost in survival. Also works on merc camps.

Indestructible: Indestructible is very strong and a good pick if you are behind in the late game and dying a lot. Storm Shield is good to help out the whole team though and not to be overlooked.

Zakarum's Witness is right. People will want to run away from your words of light but they aren't going anywhere. They will stay a while and listen to all you have to say about the church.

This may not fit your playstyle but for me it works out well. Remember Heroes is a game that is meant to be different each match. There's no real 1 build that you can just auto pick and expect to win and be good with. Notice who you are fighting and what skills they pick with TAB and answer accordingly. This is generally what I find works well but it's not a 100% concrete build. So don't give it a thumbs down because you don't have luck with it. Play what fits your style or use this as info.

Don't overextend and know that you have to rely on your team to be effective with Johanna. Don't start something you know your team isn't going to back you up on. You're not invincible and not a threat on your own. In fact she has probably the lowest damage output in the entire game. She is even bad at getting merc camps on her own because her damage output is so low it would take forever.