Rehgar is a very versatile hero that can play both support and semi-dps, depending on his choice of skills.

After playing a few games with him I've summed up the good parts and the bad parts I've found with this hero:

Good

Burst healing
Good escape mechanism (Wolf Form)
Big addition to team fights with Bloodlust
Can solo camps in mid/late game

Bad

No CC, except the totem and the talent for it
Can run short of mana if not talented

Spells

Chain Heal the focused target from the teamfight. After it hits him, it hits two additional targets. You can heal creeps/mercs as well with it, it's a good thing to do if you want to push a lane on Cursed Hollow and your team has the curse. Lighning Shield will be your most spammed skills either if you spec for healing either for dps. It gets great when it also gives you a shield and you also use it to clear jungle Earthbinding Totem is used either to kill running enemies or drop it in the middle of teamfight so entire enemy team is slowed or when you want to escape Bloodlust can turn teamfights back and I suggest taking it even when healing on certain maps (Cursed Hollow / Haunted mines / Blackhart's Bsy(Situational) Ancestral Healing is great when your carry is being focused by the enemy team, it allows him to survive and dash out more damage. It has a delay, so you should use it depending to the situation. Usually if the whole team is hitting someone you should hit it as soon as he is about 30-40$ hp Ghost Wolf is a very useful spell. It mounts you instantly, you have normal mount speed and you do not get dismounted if someone is hitting you. Very good to run out of team fights when things go south or chase enemies (Your first hit is a crit).

Level 1 - Tier 1

Spiritwalker's Grace
If you are the only healer to the team you should take this, as you tend to run out of mana after one teamfight and are useless if another fight starts soon.

Empowering Charge
If you are not the first healer or want to play semi-dps this is a good level 1 talent. It can be used on the carry to boost his damage, or on yourself if you play damage. Especially useful with Tier 6 Talent Lightning Bond.

Colossal Totem
If you plan on getting the root for the totem this would be the only case you should want this talent. Only get this if your team is REALLY low on CC.

Healing Totem
Healers alternative to Spiritwalker's Grace. It gives a 30% heal over 10 seconds if you stay in its range. It's a good talent, but I've found myself lacking mana more often when choosing this talent over Spiritwalker's Grace.

Level 4 - Tier 2

Feral Heart
Good talent that solves the mana problem a bit. It's good if you haven't taken mana reduction on tier 1, but it has no real value in team fights.

Chain Reaction
Almost always my tier 2 choice when playing healer. The 25% increased healing can help a lot on laning phase and usually a shield and heal on a target would take his HP very high, in any stages of the game.

Focused Attacks
Great talent if you are going for damage dealing. I think it scales with Ghost Wolf crit as well, so that makes it even better.

Reactive Spark
Not really a useful talent, it does not help you very much in team fights.

Farsight
Useful talent against heroes like Zeratul or Nova. If you see them in stealth and reveal them while your team is near you kill the carry of the enemy team and have a big advantage until he spawns.

Level 7 - Tier 3

Battle Momentum
Great for damage dealers. More shields, more damage. Would not really take this as support unless I'm the secondary support, but still it would be a rather odd choice.

Earth Shield
The go-to talent for healers. It is great when paired with the extra healing for lightning shielded targets and can save heroes when focused.

Shadow Wolf
If you think you might be a target in team fights and die a lot this talent could help you escape a few nasty deaths. It does not bring any real team fight value so I still would not pick it in a normal game.


Searing Attack
oth are fine, but this one depends more on the state of your mana, and you tend to low run on it with this hero if you need to heal.

Level 10 - Tier 4

Ancestral Healing
Take if you are the main healer. Be careful about the delay between cast time and it's effect, can kill people.

Bloodlust
Take if you are not the main healer or on maps that have team fights coming. Also a good pick if your lineup has heroes that benefit greatly from it.

Level 13 - Tier 5

Healing Surge
Great for any healing spec. Paired with the 25% from the lightning shield you get crazy numbers late game on first target.

Stormcaller
What I usually pick at this tier. It helps you with the mana issues, basically you cast 2 shields in 6 seconds for the price of one. Great with the shield and 25% buff

Lightning Totem
Take this if your team has very low CC or the enemy team has a lot of escape mechanisms.

Feral Lunge
Damage dealer talent. Still would not pick it over Stormcaller as it has no benefit for team fights.

Spell Shield
Not the best talent as it procs once every 30 seconds. Can save you in some situations though.

Level 16 - Tier 6

Lightning Bond
Taking this helps in many situations. In teamfights you can save team mates by casting it on them and you also gain a shield. A trick I do when clearing jungle is to cast a totem between them and shield it, thus creating two shields and clearing the jungle camp faster.

Blood for Blood
Great talent for any spec if you feel like you get bursted too fast or enemies have escape mechanisms.

Berserk
This combined with Bloodlust would be crazy on damage dealers.

Level 20 - Tier 7

Fury of the Storm
Not really a good talent, maybe works if you are damage dealer but still I would never pick it versus the ultimate upgrade

Storm Shield
It's good if they have lots of AoE, but the healing upgrades is far better than this.

Farseer's Blessing
Makes the ultimate more badass than it is right now which is, well, badass.

Gladiator's War Shout
Very good when teamfight starts and you are not there amd when minions push forts.

To be added - cannot save the post so I just post it and edit it later